The rule at our house is everyone takes naps until they're 5 years old. With our oldest, she just rested in her bed for an hour that last year because she really didn't need the sleep. But, she needed the rest time (and so did I). She watched the clock and as soon as she could get up she would. All of our others have needed the sleep. Now, on Sundays our rule is that EVERYONE (yep, even Mom and Dad) takes an hour to rest/nap. Part of our practicing the Sabbath and frankly, I love it!
When Anna turned 5 she was excited to stop taking naps. Unfortunately, she still needs the sleep even at 6. So a couple of times a week I'll tell her to come lay in my bed next to me and snuggle. I lay there and read a few pages of a book and within about 10 seconds she's asleep. Works every time. Plus, she doesn't feel like I'm making her take a nap, she just knows her body needs more sleep and thinks its funny.
***Please ignore the random blankets and pillows piled everywhere. The kids drag them in from all over the house. Also, excuse the furniture. While the 1970's are not my favorite decade for furniture, this set and the bedding were free hand-me-downs and they are serving their purpose. Normally, nobody sees this room.