diff --git a/optuna_dashboard/ts/hooks/useParamImportance.ts b/optuna_dashboard/ts/hooks/useParamImportance.ts
index 3728320f..173f1d32 100644
--- a/optuna_dashboard/ts/hooks/useParamImportance.ts
+++ b/optuna_dashboard/ts/hooks/useParamImportance.ts
@@ -17,7 +17,7 @@ export const useParamImportance = ({
     queryKey: ["paramImportance", studyId, numCompletedTrials],
     queryFn: () => getParamImportances(studyId),
     staleTime: Infinity,
-    gcTime: Infinity,
+    gcTime: 30 * 60 * 1000, // 30 minutes
   })
 
   useEffect(() => {
diff --git a/optuna_dashboard/ts/hooks/usePlot.ts b/optuna_dashboard/ts/hooks/usePlot.ts
index 594fce3f..9ce6edd9 100644
--- a/optuna_dashboard/ts/hooks/usePlot.ts
+++ b/optuna_dashboard/ts/hooks/usePlot.ts
@@ -25,7 +25,7 @@ export const usePlot = ({
       return getPlotAPI(studyId, plotType)
     },
     staleTime: Infinity,
-    gcTime: Infinity,
+    gcTime: 30 * 60 * 1000, // 30 minutes
   })
 
   return {