diff --git a/Asset/js/recoreco-modal.js b/Asset/js/recoreco-modal.js
new file mode 100644
index 0000000..9672afb
--- /dev/null
+++ b/Asset/js/recoreco-modal.js
@@ -0,0 +1,50 @@
+/*
+ * RecoReco -- keep the "days before" field within one period of the selected frequency.
+ *
+ * The Recurring schedule modal is injected by AJAX, so we react to the frequency <select> both when
+ * it appears (MutationObserver) and when it changes (delegated event). Daily -> field disabled (0);
+ * weekly -> max 6; monthly -> max 27; yearly -> max 364. The server clamps too, so this is only the
+ * UI guard.
+ */
+(function () {
+    "use strict";
+
+    var CAPS = { daily: 0, weekly: 6, monthly_day: 27, monthly_dow: 27, yearly: 364 };
+
+    function apply(select) {
+        var input = document.querySelector('input[name="recoreco_days_before"]');
+        if (! input) {
+            return;
+        }
+
+        var max = CAPS.hasOwnProperty(select.value) ? CAPS[select.value] : 27;
+
+        if (max === 0) {
+            input.value = 0;
+            input.setAttribute("max", "0");
+            input.disabled = true;
+        } else {
+            input.disabled = false;
+            input.setAttribute("max", String(max));
+            if (parseInt(input.value, 10) > max) {
+                input.value = max;
+            }
+        }
+    }
+
+    document.addEventListener("change", function (e) {
+        if (e.target && e.target.name === "recoreco_frequency") {
+            apply(e.target);
+        }
+    });
+
+    if (window.MutationObserver) {
+        new MutationObserver(function () {
+            var select = document.querySelector('select[name="recoreco_frequency"]:not([data-recoreco-init])');
+            if (select) {
+                select.setAttribute("data-recoreco-init", "1");
+                apply(select);
+            }
+        }).observe(document.body, { childList: true, subtree: true });
+    }
+})();
diff --git a/Controller/RecurrenceController.php b/Controller/RecurrenceController.php
index dedc7d8..684f72f 100644
--- a/Controller/RecurrenceController.php
+++ b/Controller/RecurrenceController.php
@@ -46,12 +46,16 @@ class RecurrenceController extends BaseController
             ? $input['recoreco_frequency']
             : 'monthly_day';
 
+        // Keep the lead time under one period (else a copy's fire time crosses the prior occurrence).
+        $daysBefore = isset($input['recoreco_days_before']) && ctype_digit((string) $input['recoreco_days_before']) ? (int) $input['recoreco_days_before'] : 0;
+        $daysBefore = min($daysBefore, $this->maxDaysBefore($frequency));
+
         $values = array(
             'recoreco_enabled' => $enabled,
             'recoreco_target_column' => isset($input['recoreco_target_column']) ? (int) $input['recoreco_target_column'] : (int) $task['column_id'],
             'recoreco_frequency' => $frequency,
             'recoreco_last_day' => isset($input['recoreco_last_day']) ? 1 : 0,
-            'recoreco_days_before' => isset($input['recoreco_days_before']) && ctype_digit((string) $input['recoreco_days_before']) ? (int) $input['recoreco_days_before'] : 0,
+            'recoreco_days_before' => $daysBefore,
             'recoreco_link_copies' => isset($input['recoreco_link_copies']) ? 1 : 0,
         );
 
@@ -97,4 +101,22 @@ class RecurrenceController extends BaseController
             'daily' => t('Daily'),
         );
     }
+
+    /**
+     * The largest allowed "days before" for a frequency -- kept strictly under one period so a
+     * copy's fire time never crosses the previous occurrence. Daily = 0 (disabled).
+     */
+    private function maxDaysBefore($frequency)
+    {
+        switch ($frequency) {
+            case 'daily':
+                return 0;
+            case 'weekly':
+                return 6;
+            case 'yearly':
+                return 364;
+            default: // monthly_day, monthly_dow
+                return 27;
+        }
+    }
 }
diff --git a/Plugin.php b/Plugin.php
index 3cf350e..e98950f 100644
--- a/Plugin.php
+++ b/Plugin.php
@@ -12,6 +12,11 @@ class Plugin extends Base
         // (next to native "Edit recurrence"). Opens the RecoReco config modal.
         $this->template->hook->attach('template:task:sidebar:after-basic-actions', 'recoReco:task/sidebar_action');
 
+        // Modal JS: keep "days before" within one period of the selected frequency.
+        $this->hook->on('template:layout:js', array(
+            'template' => 'plugins/RecoReco/Asset/js/recoreco-modal.js',
+        ));
+
         // The scheduling engine runs from the CLI (cron). Registered CLI-only so web requests do
         // not build the console app.
         if (php_sapi_name() === 'cli') {
@@ -36,7 +41,7 @@ class Plugin extends Base
 
     public function getPluginVersion()
     {
-        return '1.1.0';
+        return '1.1.1';
     }
 
     public function getPluginHomepage()
diff --git a/VERSION b/VERSION
index f6d943c..e127cbb 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-RecoReco v1.1
+RecoReco v1.1.1