We did 2/3/4 method at this age. So up for two hours in the morning then a short nap for about 50 minutes, then stays up for three hours and has long nap for up to 2 hours, then up for four hours then bed.
My twins dropped a morning nap by 11 months. They're now 16 months and although occasionally they'll have 2 hours in the afternoon, it can be as little as 40 mins, and very rarely not at all. They just do not like sleeping.
15mo can get by on one nap. I do like to try him with two on the days he's at home with me, even if it's just 20 mins in the morning to take the edge off. He sleeps a good 12 hours solid at night though which does help.