N.M.
Every child is different. My daughter went to one nap early on before a year, and gave up naps all together right around age 2. We institued "quite time" instead. She would spend this time in her room playing quietly, sometimes she would actually fall asleep.
My son went to one nap around a year and held onto that nap until about 3. After that it was hit and miss. He just over 4 now and will still fall asleep on the couch in the later afternoons now and then for a little power nap.
It is said that everyone needs a specified amount of sleep but I don't believe it to be true. I think everyone has their own "schedule" and the amount of sleep a person, even a child, needs is unique.