M is 8 months and for the most part, has 3 naps.

6:30am wake-up
8:30am nap 1 for 1 hour 30 mins
1:00pm nap 2 for 1 hour 30 mins
5:30pm short nap 3
8/8:30pm bedtime

some days she has 2 really long naps so we skip the 3rd one and put her to bed at 7:30pm. my question is- when did you strictly stick to a 2 nap schedule, regardless of how long the naps were? does too long of an awake time make much of a difference as they get older?