The older a child is, the more difficult it is to convince them of the benefits of a diaper. For example, for a longer car ride or to be able to sleep undisturbed. That's why it's important that diapers are seen as something normal. It is an additional piece of clothing of the child, which has a useful purpose. This way, even an older child can wear a diaper under his clothes without any problems.
We have an older boy who still wears diapers regularly, during the day and at night. For him, it is quite normal to lie on the changing table before a car ride. This allows us to have carefree car rides and he enjoys that as well. We are quite easygoing with diapers at in our family, and that's why he still likes to wear them. We also still have a changing table and blog about it:
https://tobischangingtable.wordpress.com/