How long does your baby nap?

Sarah
How long and how often do your babies nap? My daughter is 14 weeks and sleeps 9pm-7am waking once during the night to eat. During the day she naps for about 40-60 minutes, every hour and a half. We don't do any sort of schedule, she just naturally gets sleepy every 90 minutes. Do other mamas schedule naps or just let baby tell you when they are sleepy?