My daughter is 4 mos old and takes 3 or 4 naps a day. I nurse her to sleep in our bed, or wear her for naps. Her first nap of the day lasts about 45 minutes, but the later ones are a bit of a crap shoot.

She just woke up after a 30 minute nap, and I'm trying to get her back to sleep.
Usually if its less than 45 minutes, I try to get her to sleep longer (by nursing her to sleep again, sometimes for as long as 20 minutes), but I'm wondering if maybe I shouldn't?