Interesting thread...I'm quite obsessed with naps nowadays (as opposed to being obsessed with feeding for the first 3 months!)
My DD is 4.5 months and sleeps 7.30pm til 6.30/7am at night, with a dream feed at 11pm.
Her naps are all a bit random and she needs plenty of winding down time to drop off for a nap. Any stimulation during the winding down phase (being in a cafe, people chatting to her, things to look at, loud buses going past) leads to sudden grizzly meltdown when she wants to sleep...now! When I'm out and about I tend to forget/not notice the signs that she wants to wind down, so we have grizzly meltdown, whereas when I'm at home, she will often go into her spaced out winding down phase more obviously, so I take away any toys, pop in her dummy and tuck blanket over her.
I started trying to get her to nap in her cot during the day but it took so long to get her to sleep, then she'd only sleep for 30 mins, it didn't seem worth it. Plus I can't go anywhere if she can only nap in her cot, so now I tend to let her nap in her bouncy chair or in the pram.
Her natural pattern of naps seems to be...
(first feed of day 7.15am ish)
Starts winding down 8.30am
Asleep (with a bit of help) 9.00am
Naps for 45 mins
(2nd feed of the day 11am ish)
Starts winding down 11.45ish
Asleep (with a bit of help) 12pm
Sometimes only naps for 45 mins, sometimes goes for 2 hours - can't seem to find a reason why one or the other
(3rd feed of the day 3pm ish)
Then naps all get very random and short. She usually has a couple between the 3pm feed and the 6.30pm feed, but she's usually very grizzly before, often needs to be held and rocked to sleep after getting very agitated, and sometimes only naps for 15 mins!
Not sure if that's because by the afternoon I've stopped observing her as closely so miss the important signals or what, but afternoon are a bit of a nap disaster zone in our house.
(4th feed of the day 6.30/7pm ish)
Bath (if she's having one) 7pm ish
Bed by 7.30pm
I wouldn't worry about naps at all if she didn't get so upset when she wants to sleep but can't. It's the only time she really cries at all, and it's quite tragic sobbing she does, with tears and everything!