An even better reminder IMHO is to just drink plenty of water, then your body tells you when it's time to get up and empty your bladder (and refill the glass).

An even better reminder IMHO is to just drink plenty of water, then your body tells you when it's time to get up and empty your bladder (and refill the glass). I've been using this method for ~25 years without the need for digital reminders. My glass holds 0,5 Liters of water and that's usually the limit for my bladder.