DS2 is 10 weeks. Currently he has 4 naps a day - approx. 9am for about 45 mins, 11am-1.30/2ish, 3pm for 45 mins and 5pm for 45 mins.
I know DS1 went to 3 naps at some point but I can't remember when!
At the moment DS2 goes to bed around 8-8.30pm and sleeps til about 8am (with multiple night feeds).