diff --git a/.vscode.dist/settings.json b/.vscode.dist/settings.json
index a3338ec6462..690b5bda024 100644
--- a/.vscode.dist/settings.json
+++ b/.vscode.dist/settings.json
@@ -2,7 +2,7 @@
     "editor.formatOnSave": true,
     "[python]": {
         "editor.codeActionsOnSave": {
-            "source.organizeImports": true
+            "source.organizeImports": "explicit"
         }
     },
     "files.watcherExclude": {
diff --git a/Cargo.lock b/Cargo.lock
index 63078a33435..6d665180005 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2099,7 +2099,7 @@ dependencies = [
 [[package]]
 name = "fsrs"
 version = "3.0.0"
-source = "git+https://github.com/open-spaced-repetition/fsrs-rs.git?rev=96520531415e032781adfe212f8a5eed216006be#96520531415e032781adfe212f8a5eed216006be"
+source = "git+https://github.com/open-spaced-repetition/fsrs-rs.git?rev=22f8e453c120f5bc5996f86558a559c6b7abfc49#22f8e453c120f5bc5996f86558a559c6b7abfc49"
 dependencies = [
  "burn",
  "itertools 0.12.1",
diff --git a/Cargo.toml b/Cargo.toml
index 6bd0c35e183..e3299a740e1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -37,7 +37,7 @@ rev = "184b2ca50ed39ca43da13f0b830a463861adb9ca"
 [workspace.dependencies.fsrs]
 # version = "=2.0.3"
 git = "https://github.com/open-spaced-repetition/fsrs-rs.git"
-rev = "96520531415e032781adfe212f8a5eed216006be"
+rev = "22f8e453c120f5bc5996f86558a559c6b7abfc49"
 # path = "../open-spaced-repetition/fsrs-rs"
 
 [workspace.dependencies]
diff --git a/proto/anki/scheduler.proto b/proto/anki/scheduler.proto
index b657ff3fa24..42befe816dc 100644
--- a/proto/anki/scheduler.proto
+++ b/proto/anki/scheduler.proto
@@ -393,6 +393,7 @@ message SimulateFsrsReviewRequest {
   bool new_cards_ignore_review_limit = 9;
   repeated float easy_days_percentages = 10;
   deck_config.DeckConfig.Config.ReviewCardOrder review_order = 11;
+  optional uint32 suspend_after_lapse_count = 12;
 }
 
 message SimulateFsrsReviewResponse {
@@ -409,6 +410,7 @@ message ComputeOptimalRetentionRequest {
   string search = 4;
   double loss_aversion = 5;
   repeated float easy_days_percentages = 6;
+  optional uint32 suspend_after_lapse_count = 7;
 }
 
 message ComputeOptimalRetentionResponse {
diff --git a/rslib/src/scheduler/fsrs/retention.rs b/rslib/src/scheduler/fsrs/retention.rs
index c89c08aab52..23df5b33a1e 100644
--- a/rslib/src/scheduler/fsrs/retention.rs
+++ b/rslib/src/scheduler/fsrs/retention.rs
@@ -44,9 +44,9 @@ impl Collection {
         let post_scheduling_fn: Option<PostSchedulingFn> =
             if self.get_config_bool(BoolKey::LoadBalancerEnabled) {
                 Some(PostSchedulingFn(Arc::new(
-                    move |interval, max_interval, today, due_cnt_per_day, rng| {
+                    move |card, max_interval, today, due_cnt_per_day, rng| {
                         apply_load_balance_and_easy_days(
-                            interval,
+                            card.interval,
                             max_interval,
                             today,
                             due_cnt_per_day,
@@ -78,6 +78,7 @@ impl Collection {
                     learn_limit,
                     review_limit: usize::MAX,
                     new_cards_ignore_review_limit: true,
+                    suspend_after_lapses: None,
                     post_scheduling_fn,
                     review_priority_fn: None,
                 },
diff --git a/rslib/src/scheduler/fsrs/simulator.rs b/rslib/src/scheduler/fsrs/simulator.rs
index 1cfc2e959bc..34bec1317f9 100644
--- a/rslib/src/scheduler/fsrs/simulator.rs
+++ b/rslib/src/scheduler/fsrs/simulator.rs
@@ -142,11 +142,13 @@ impl Collection {
             .min(req.new_limit as usize);
         if req.new_limit > 0 {
             let new_cards = (0..new_cards).map(|i| fsrs::Card {
+                id: -(i as i64),
                 difficulty: f32::NEG_INFINITY,
                 stability: 1e-8,              // Not filtered by fsrs-rs
                 last_date: f32::NEG_INFINITY, // Treated as a new card in simulation
                 due: ((introduced_today_count + i) / req.new_limit as usize) as f32,
                 interval: f32::NEG_INFINITY,
+                lapses: 0,
             });
             converted_cards.extend(new_cards);
         }
@@ -159,9 +161,9 @@ impl Collection {
         let post_scheduling_fn: Option<PostSchedulingFn> =
             if self.get_config_bool(BoolKey::LoadBalancerEnabled) {
                 Some(PostSchedulingFn(Arc::new(
-                    move |interval, max_interval, today, due_cnt_per_day, rng| {
+                    move |card, max_interval, today, due_cnt_per_day, rng| {
                         apply_load_balance_and_easy_days(
-                            interval,
+                            card.interval,
                             max_interval,
                             today,
                             due_cnt_per_day,
@@ -198,6 +200,7 @@ impl Collection {
             learn_limit: req.new_limit as usize,
             review_limit: req.review_limit as usize,
             new_cards_ignore_review_limit: req.new_cards_ignore_review_limit,
+            suspend_after_lapses: req.suspend_after_lapse_count,
             post_scheduling_fn,
             review_priority_fn,
         };
@@ -234,21 +237,25 @@ impl Card {
                     let relative_due = due - days_elapsed;
                     let last_date = (relative_due - card.interval as i32).min(0) as f32;
                     Some(fsrs::Card {
+                        id: card.id.0,
                         difficulty: state.difficulty,
                         stability: state.stability,
                         last_date,
                         due: relative_due as f32,
                         interval: card.interval as f32,
+                        lapses: card.lapses,
                     })
                 }
                 CardQueue::New => None,
                 CardQueue::Learn | CardQueue::SchedBuried | CardQueue::UserBuried => {
                     Some(fsrs::Card {
+                        id: card.id.0,
                         difficulty: state.difficulty,
                         stability: state.stability,
                         last_date: 0.0,
                         due: 0.0,
                         interval: card.interval as f32,
+                        lapses: card.lapses,
                     })
                 }
                 CardQueue::PreviewRepeat => None,
diff --git a/ts/routes/deck-options/EasyDays.svelte b/ts/routes/deck-options/EasyDays.svelte
index aea4e026e04..e1fe4507d67 100644
--- a/ts/routes/deck-options/EasyDays.svelte
+++ b/ts/routes/deck-options/EasyDays.svelte
@@ -9,6 +9,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     import TitledContainer from "$lib/components/TitledContainer.svelte";
     import type { DeckOptionsState } from "./lib";
     import Warning from "./Warning.svelte";
+    import EasyDaysInput from "./EasyDaysInput.svelte";
 
     export let state: DeckOptionsState;
     export let api: Record<string, never>;
@@ -35,16 +36,6 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         easyDaysChanged && !($fsrsEnabled && $reschedule)
             ? tr.deckConfigEasyDaysChange()
             : "";
-
-    const easyDays = [
-        tr.deckConfigEasyDaysMonday(),
-        tr.deckConfigEasyDaysTuesday(),
-        tr.deckConfigEasyDaysWednesday(),
-        tr.deckConfigEasyDaysThursday(),
-        tr.deckConfigEasyDaysFriday(),
-        tr.deckConfigEasyDaysSaturday(),
-        tr.deckConfigEasyDaysSunday(),
-    ];
 </script>
 
 <datalist id="easy_day_steplist">
@@ -53,43 +44,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
 <TitledContainer title={tr.deckConfigEasyDaysTitle()}>
     <DynamicallySlottable slotHost={Item} {api}>
-        <Item>
-            <div class="easy-days-settings">
-                <table>
-                    <thead>
-                        <tr>
-                            <th></th>
-                            <th class="header min-col">
-                                <span>{tr.deckConfigEasyDaysMinimum()}</span>
-                            </th>
-                            <th class="header text-center">
-                                <span>{tr.deckConfigEasyDaysReduced()}</span>
-                            </th>
-                            <th class="header normal-col">
-                                <span>{tr.deckConfigEasyDaysNormal()}</span>
-                            </th>
-                        </tr>
-                    </thead>
-                    <tbody>
-                        {#each easyDays as day, index}
-                            <tr>
-                                <td class="day">{day}</td>
-                                <td colspan="3">
-                                    <input
-                                        type="range"
-                                        bind:value={$config.easyDaysPercentages[index]}
-                                        step={0.5}
-                                        max={1.0}
-                                        min={0.0}
-                                        list="easy_day_steplist"
-                                    />
-                                </td>
-                            </tr>
-                        {/each}
-                    </tbody>
-                </table>
-            </div>
-        </Item>
+        <EasyDaysInput bind:values={$config.easyDaysPercentages} />
         <Item>
             <Warning warning={noNormalDay} />
         </Item>
@@ -98,36 +53,3 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         </Item>
     </DynamicallySlottable>
 </TitledContainer>
-
-<style>
-    .easy-days-settings table {
-        width: 100%;
-        border-collapse: collapse;
-        table-layout: fixed;
-    }
-    .easy-days-settings th,
-    .easy-days-settings td {
-        padding: 8px;
-        border-bottom: var(--border) solid 1px;
-    }
-    .header {
-        word-wrap: break-word;
-        font-size: smaller;
-    }
-    .easy-days-settings input[type="range"] {
-        width: 100%;
-    }
-
-    .day {
-        word-wrap: break-word;
-        font-size: smaller;
-    }
-
-    .min-col {
-        text-align: start;
-    }
-
-    .normal-col {
-        text-align: end;
-    }
-</style>
diff --git a/ts/routes/deck-options/EasyDaysInput.svelte b/ts/routes/deck-options/EasyDaysInput.svelte
new file mode 100644
index 00000000000..a7c13e2e211
--- /dev/null
+++ b/ts/routes/deck-options/EasyDaysInput.svelte
@@ -0,0 +1,91 @@
+<!--
+Copyright: Ankitects Pty Ltd and contributors
+License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+-->
+<script>
+    import * as tr from "@generated/ftl";
+    import Item from "$lib/components/Item.svelte";
+
+    const easyDays = [
+        tr.deckConfigEasyDaysMonday(),
+        tr.deckConfigEasyDaysTuesday(),
+        tr.deckConfigEasyDaysWednesday(),
+        tr.deckConfigEasyDaysThursday(),
+        tr.deckConfigEasyDaysFriday(),
+        tr.deckConfigEasyDaysSaturday(),
+        tr.deckConfigEasyDaysSunday(),
+    ];
+
+    export let values = [0, 0, 0, 0, 0, 0, 0];
+</script>
+
+<Item>
+    <div class="easy-days-settings">
+        <table>
+            <thead>
+                <tr>
+                    <th></th>
+                    <th class="header min-col">
+                        <span>{tr.deckConfigEasyDaysMinimum()}</span>
+                    </th>
+                    <th class="header text-center">
+                        <span>{tr.deckConfigEasyDaysReduced()}</span>
+                    </th>
+                    <th class="header normal-col">
+                        <span>{tr.deckConfigEasyDaysNormal()}</span>
+                    </th>
+                </tr>
+            </thead>
+            <tbody>
+                {#each easyDays as day, index}
+                    <tr>
+                        <td class="day">{day}</td>
+                        <td colspan="3">
+                            <input
+                                type="range"
+                                bind:value={values[index]}
+                                step={0.5}
+                                max={1.0}
+                                min={0.0}
+                                list="easy_day_steplist"
+                            />
+                        </td>
+                    </tr>
+                {/each}
+            </tbody>
+        </table>
+    </div>
+</Item>
+
+<style>
+    .easy-days-settings table {
+        width: 100%;
+        border-collapse: collapse;
+        table-layout: fixed;
+    }
+    .easy-days-settings th,
+    .easy-days-settings td {
+        padding: 8px;
+        border-bottom: var(--border) solid 1px;
+    }
+    .header {
+        word-wrap: break-word;
+        font-size: smaller;
+    }
+    .easy-days-settings input[type="range"] {
+        width: 100%;
+    }
+
+    .day {
+        word-wrap: break-word;
+        font-size: smaller;
+    }
+
+    .min-col {
+        text-align: start;
+    }
+
+    .normal-col {
+        text-align: end;
+    }
+</style>
diff --git a/ts/routes/deck-options/SimulatorModal.svelte b/ts/routes/deck-options/SimulatorModal.svelte
index 6bb30620c53..1b587c98540 100644
--- a/ts/routes/deck-options/SimulatorModal.svelte
+++ b/ts/routes/deck-options/SimulatorModal.svelte
@@ -28,6 +28,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     import SpinBoxFloatRow from "./SpinBoxFloatRow.svelte";
     import { reviewOrderChoices } from "./choices";
     import EnumSelectorRow from "$lib/components/EnumSelectorRow.svelte";
+    import { DeckConfig_Config_LeechAction } from "@generated/anki/deck_config_pb";
+    import EasyDaysInput from "./EasyDaysInput.svelte";
 
     export let shown = false;
     export let state: DeckOptionsState;
@@ -48,6 +50,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     let points: Point[] = [];
     const newCardsIgnoreReviewLimit = state.newCardsIgnoreReviewLimit;
     let smooth = true;
+    let suspendLeeches = $config.leechAction == DeckConfig_Config_LeechAction.SUSPEND;
+    let leechThreshold = $config.leechThreshold;
 
     $: daysToSimulate = 365;
     $: deckSize = 0;
@@ -75,6 +79,10 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         let resp: SimulateFsrsReviewResponse | undefined;
         simulateFsrsRequest.daysToSimulate = daysToSimulate;
         simulateFsrsRequest.deckSize = deckSize;
+        simulateFsrsRequest.suspendAfterLapseCount = suspendLeeches
+            ? leechThreshold
+            : undefined;
+        simulateFsrsRequest.easyDaysPercentages = easyDayPercentages;
         try {
             await runWithBackendProgress(
                 async () => {
@@ -169,6 +177,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
             simulateSubgraph,
         );
     }
+
+    let easyDayPercentages = [...$config.easyDaysPercentages];
 </script>
 
 <div class="modal" class:show={shown} class:d-block={shown} tabindex="-1">
@@ -235,41 +245,88 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
                     </SettingTitle>
                 </SpinBoxRow>
 
-                <SpinBoxRow
-                    bind:value={simulateFsrsRequest.maxInterval}
-                    defaultValue={$config.maximumReviewInterval}
-                    min={1}
-                    max={36500}
-                >
-                    <SettingTitle on:click={() => openHelpModal("simulateFsrsReview")}>
-                        {tr.schedulingMaximumInterval()}
-                    </SettingTitle>
-                </SpinBoxRow>
-
-                <EnumSelectorRow
-                    bind:value={simulateFsrsRequest.reviewOrder}
-                    defaultValue={$config.reviewOrder}
-                    choices={reviewOrderChoices($fsrs)}
-                >
-                    <SettingTitle on:click={() => openHelpModal("simulateFsrsReview")}>
-                        {tr.deckConfigReviewSortOrder()}
-                    </SettingTitle>
-                </EnumSelectorRow>
-
-                <SwitchRow
-                    bind:value={simulateFsrsRequest.newCardsIgnoreReviewLimit}
-                    defaultValue={$newCardsIgnoreReviewLimit}
-                >
-                    <SettingTitle on:click={() => openHelpModal("simulateFsrsReview")}>
-                        <GlobalLabel title={tr.deckConfigNewCardsIgnoreReviewLimit()} />
-                    </SettingTitle>
-                </SwitchRow>
-
-                <SwitchRow bind:value={smooth} defaultValue={true}>
-                    <SettingTitle on:click={() => openHelpModal("simulateFsrsReview")}>
-                        {"Smooth Graph"}
-                    </SettingTitle>
-                </SwitchRow>
+                <details>
+                    <summary>{tr.deckConfigEasyDaysTitle()}</summary>
+                    {#key easyDayPercentages}
+                        <EasyDaysInput bind:values={easyDayPercentages} />
+                    {/key}
+                </details>
+
+                <details>
+                    <summary>{"Advanced settings"}</summary>
+                    <SpinBoxRow
+                        bind:value={simulateFsrsRequest.maxInterval}
+                        defaultValue={$config.maximumReviewInterval}
+                        min={1}
+                        max={36500}
+                    >
+                        <SettingTitle
+                            on:click={() => openHelpModal("simulateFsrsReview")}
+                        >
+                            {tr.schedulingMaximumInterval()}
+                        </SettingTitle>
+                    </SpinBoxRow>
+
+                    <EnumSelectorRow
+                        bind:value={simulateFsrsRequest.reviewOrder}
+                        defaultValue={$config.reviewOrder}
+                        choices={reviewOrderChoices($fsrs)}
+                    >
+                        <SettingTitle
+                            on:click={() => openHelpModal("simulateFsrsReview")}
+                        >
+                            {tr.deckConfigReviewSortOrder()}
+                        </SettingTitle>
+                    </EnumSelectorRow>
+
+                    <SwitchRow
+                        bind:value={simulateFsrsRequest.newCardsIgnoreReviewLimit}
+                        defaultValue={$newCardsIgnoreReviewLimit}
+                    >
+                        <SettingTitle
+                            on:click={() => openHelpModal("simulateFsrsReview")}
+                        >
+                            <GlobalLabel
+                                title={tr.deckConfigNewCardsIgnoreReviewLimit()}
+                            />
+                        </SettingTitle>
+                    </SwitchRow>
+
+                    <SwitchRow bind:value={smooth} defaultValue={true}>
+                        <SettingTitle
+                            on:click={() => openHelpModal("simulateFsrsReview")}
+                        >
+                            {"Smooth Graph"}
+                        </SettingTitle>
+                    </SwitchRow>
+
+                    <SwitchRow
+                        bind:value={suspendLeeches}
+                        defaultValue={$config.leechAction ==
+                            DeckConfig_Config_LeechAction.SUSPEND}
+                    >
+                        <SettingTitle
+                            on:click={() => openHelpModal("simulateFsrsReview")}
+                        >
+                            {"Suspend Leeches"}
+                        </SettingTitle>
+                    </SwitchRow>
+
+                    {#if suspendLeeches}
+                        <SpinBoxRow
+                            bind:value={leechThreshold}
+                            defaultValue={$config.leechThreshold}
+                            min={1}
+                            max={9999}
+                        >
+                            <SettingTitle
+                                on:click={() => openHelpModal("simulateFsrsReview")}
+                            >
+                                {tr.schedulingLeechThreshold()}
+                            </SettingTitle>
+                        </SpinBoxRow>
+                    {/if}
+                </details>
 
                 <button
                     class="btn {computing ? 'btn-warning' : 'btn-primary'}"
@@ -298,6 +355,11 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
                         $newCardsIgnoreReviewLimit =
                             simulateFsrsRequest.newCardsIgnoreReviewLimit;
                         $config.reviewOrder = simulateFsrsRequest.reviewOrder;
+                        $config.leechAction = suspendLeeches
+                            ? DeckConfig_Config_LeechAction.SUSPEND
+                            : DeckConfig_Config_LeechAction.TAG_ONLY;
+                        $config.leechThreshold = leechThreshold;
+                        $config.easyDaysPercentages = [...easyDayPercentages];
                         onPresetChange();
                     }}
                 >
@@ -339,15 +401,17 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
                         </InputBox>
                     </div>
 
-                    <svg
-                        bind:this={svg}
-                        viewBox={`0 0 ${bounds.width} ${bounds.height}`}
-                    >
-                        <CumulativeOverlay />
-                        <HoverColumns />
-                        <AxisTicks {bounds} />
-                        <NoDataOverlay {bounds} />
-                    </svg>
+                    <div class="svg-container">
+                        <svg
+                            bind:this={svg}
+                            viewBox={`0 0 ${bounds.width} ${bounds.height}`}
+                        >
+                            <CumulativeOverlay />
+                            <HoverColumns />
+                            <AxisTicks {bounds} />
+                            <NoDataOverlay {bounds} />
+                        </svg>
+                    </div>
 
                     <TableData {tableData} />
                 </Graph>
@@ -359,6 +423,27 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 <style>
     .modal {
         background-color: rgba(0, 0, 0, 0.5);
+        --bs-modal-margin: 0;
+    }
+
+    .svg-container {
+        width: 100%;
+        max-height: calc(100vh - 400px); /* Account for modal header, controls, etc */
+        aspect-ratio: 600 / 250;
+        display: flex;
+        align-items: center;
+    }
+
+    svg {
+        width: 100%;
+        height: 100%;
+    }
+
+    .modal-header {
+        position: sticky;
+        top: 0;
+        background-color: var(--bs-body-bg);
+        z-index: 100;
     }
 
     :global(.modal-xl) {
@@ -372,4 +457,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     .btn {
         margin-bottom: 0.375rem;
     }
+
+    summary {
+        margin-bottom: 0.5em;
+    }
 </style>