Samsung
Turn Notification Reminders On or Off auf Samsung
Samsung phones announce a new notification only once by default. Depending on the active sound mode, you get a short tone, a vibration, or both, and then the alert stays silent even if you never open it.
The Notification reminders feature closes that gap. Once enabled, the system repeats the alert at a fixed interval for any app you select, until you open the notification or dismiss it.
This is useful for calls, messages, or emails you tend to overlook when the phone is in your pocket or on silent for a while. It is less useful for apps that already send frequent updates, since repeated reminders on top of that can feel excessive.
Where to find the setting
Go to Settings ➔ Notifications ➔ Advanced settings ➔ Notification reminders. Toggle the feature on or off with the switch at the top.
Below the switch, open the app list and pick which apps should trigger the repeated reminder. Only checked apps will receive follow-up alerts; all others behave as before, with a single notification only.