My girls were each trained just before their third birthday. I did put a pullup on them to go to bed, but it was never really wet. I stopped when they were four.
My son was trained at about 3 1/2. He took a little longer than the girls to have a bowel movement ont he toilet. I kept pullups on him to go to preschool and for bed for an extra month or two just to be safe.
I didn't rush them, and they never had accidents.