If your rule is one hour of games a day, make the phone match the rule.
Put games into one group. Decide when the group can open. When the hour ends, lock the group again and keep downloads, purchase prompts, and game-related social entries controlled.
This works better than repeating the same reminder every day. Children understand stable routines more easily than moving limits.
iPhone Locker helps parents prepare a game-time setup that can be switched on and off with less friction.