Some of us in our age already have 3 daytime naps and we still have 4.…

Some of us in our age already have 3 daytime naps and we still have 4. I'm thinking maybe that's why he sleeps for 30-40 minutes. Maybe it's time for 3 naps then he will sleep longer? Or do your kids also sleep for 30-40 mins? What if we switch to 3 naps? How do we do that? I tried once but he can't handle it, cries, and I can't distract him anymore, and I end up sleeping too. I just think he doesn't get enough rest in those half an hour and that's why he cries instead of playing.