I think my two in a half year old is starting the paper work for not taking naps. It has started everyday for the last couple of weeks, when I lay her down she cries and does not go to sleep until after two or not at all. She then will not go to sleep until 10 at night. I put her in bed around 8:30 PM. Whether she sleeps or not is her decision but she will be in her crib from 1 until 3:30 or so because I have things I need to get done such as cleaning, cooking, working on consignment stuff to sell.
I was talking to my friend and her daughter is doing the same thing. If she does nap she does not want to go to sleep until 9 or 10, and if she does not sleep, she is melting down at 6. Now Peanut can hold her own, she may get grumpy but she typically does not melt down even without a nap. Pookie was awful without her nap. She would tantrum and scream around 5 everyday until after age 3.