DD is 20months and has one nap a day, about 12, and can nap from 30mins to 2.5 hours. I've recently noticed that the longer she naps during the day, the earlier she is up the next morning, so thinking of cutting it to max 1 hour.
Interested to hear from other people with children of a similar age and when/how long they nap for.
I should also add - her sleep is notoriously bad and daytime naps didn't seem to make a difference. Recently she has started sleeping a lot better which is how I've noticed the effect daytime sleep has