only clear cache if it hasnt been done in a while

src/Android/Services/DeviceActionService.cs

@@ -11,6 +11,13 @@ namespace Bit.Android.Services
 {
     public class DeviceActionService : IDeviceActionService
     {
+        private readonly IAppSettingsService _appSettingsService;
+
+        public DeviceActionService(IAppSettingsService appSettingsService)
+        {
+            _appSettingsService = appSettingsService;
+        }
+
         public void CopyToClipboard(string text)
         {
             var clipboardManager = (ClipboardManager)Forms.Context.GetSystemService(Context.ClipboardService);
@@ -86,6 +93,7 @@ namespace Bit.Android.Services
             try
             {
                 DeleteDir(CrossCurrentActivity.Current.Activity.CacheDir);
+                _appSettingsService.LastCacheClear = DateTime.UtcNow;
             }
             catch(Exception) { }
         }

src/App/Abstractions/Services/IAppSettingsService.cs

@@ -6,6 +6,7 @@ namespace Bit.App.Abstractions
     {
         bool Locked { get; set; }
         DateTime LastActivity { get; set; }
+        DateTime LastCacheClear { get; set; }
         bool AutofillPersistNotification { get; set; }
         bool AutofillPasswordField { get; set; }
         string SecurityStamp { get; set; }

src/App/App.cs

@@ -113,7 +113,11 @@ namespace Bit.App
                 await Task.Run(() => FullSyncAsync()).ConfigureAwait(false);
             }
 
-            await Task.Run(() => _deviceActionService.ClearCache()).ConfigureAwait(false);
+            if((DateTime.UtcNow - _appSettingsService.LastCacheClear).TotalDays >= 1)
+            {
+                await Task.Run(() => _deviceActionService.ClearCache()).ConfigureAwait(false);
+            }
+
             Debug.WriteLine("OnStart");
         }
 
@@ -156,6 +160,13 @@ namespace Bit.App
             {
                 await Task.Run(() => FullSyncAsync()).ConfigureAwait(false);
             }
+
+            var now = DateTime.UtcNow;
+            if((now - _appSettingsService.LastCacheClear).TotalDays >= 1
+                && (now - _appSettingsService.LastActivity).TotalHours >= 1)
+            {
+                await Task.Run(() => _deviceActionService.ClearCache()).ConfigureAwait(false);
+            }
         }
 
         private void SetMainPageFromAutofill()

src/App/Constants.cs

@@ -28,6 +28,7 @@
 
         public const string SecurityStamp = "other:securityStamp";
         public const string LastActivityDate = "other:lastActivityDate";
+        public const string LastCacheClearDate = "other:cacheClearDate";
         public const string Locked = "other:locked";
         public const string LastLoginEmail = "other:lastLoginEmail";
         public const string LastSync = "other:lastSync";

src/App/Services/AppSettingsService.cs

@@ -38,6 +38,18 @@ namespace Bit.App.Services
             }
         }
 
+        public DateTime LastCacheClear
+        {
+            get
+            {
+                return _settings.GetValueOrDefault(Constants.LastCacheClearDate, DateTime.MinValue);
+            }
+            set
+            {
+                _settings.AddOrUpdateValue(Constants.LastCacheClearDate, value);
+            }
+        }
+
         public bool AutofillPersistNotification
         {
             get

src/iOS/Services/DeviceActionService.cs

@@ -8,6 +8,13 @@ namespace Bit.iOS.Services
 {
     public class DeviceActionService : IDeviceActionService
     {
+        private readonly IAppSettingsService _appSettingsService;
+
+        public DeviceActionService(IAppSettingsService appSettingsService)
+        {
+            _appSettingsService = appSettingsService;
+        }
+
         public void CopyToClipboard(string text)
         {
             UIPasteboard clipboard = UIPasteboard.General;
@@ -44,6 +51,8 @@ namespace Bit.iOS.Services
                     NSFileManager.DefaultManager.Remove(item, out itemError);
                 }
             }
+
+            _appSettingsService.LastCacheClear = DateTime.UtcNow;
         }
 
         private UIViewController GetVisibleViewController(UIViewController controller = null)