Mostly I'd go with his mood, try to give him some quiet time if you can (sitting in a quiet room reading stories to him if he won't stay on his own) and try for about the same awake hours as he has when he does nap.
I know my niece had given up naps by 2.5yo & my SIL had her pretty much 12hour & 12 hour with both (her and child) having a rest period as SIL was pregnant, in the middle of the day where they spent 45mins on the parent's bed listening to music & quiet play or reading.