“And remind, for indeed, the reminder benefits the believers.”
Notice how your kids read the same books dozens of times?
Kids love repetition and each time they read a book, they get something new out of it.
You can use that to your advantage.
Whenever you want to teach your kids something, be it Islamic or anything else, don’t hesitate to repeat what you taught them.
Each time they hear the lesson, they will learn something new.