I have always loosely scheduled naps for the girls. Pretty much whenever they want to sleep they can, especially during the week.
For instance, Annika typically wakes up on the weekdays around 8am. She goes into the bedroom with Josh so he can rest some more (he goes to bed at 4am after getting home from work) and she usually watches a movie or plays with her toys. Then when I pick up the girls from Josh Annika is usually asleep. She naps during the 20 minute drive home. Once we get home though I wake her up! It's already around 4pm when we get home and this is just too late in my opinion for a nap. I like to get her into bed by 8-8:30pm so that I can shower and get my things together for work. I have let her continue to nap, by carefully caring her into the house and laying her on the couch, but when I do this she naps till after 6pm and then decides she wants to play till 10pm!
Weekends are different. She still wakes up at 8am but since we're so active she has to take a nap by noon or she has a meltdown. Sometimes she'll sleep almost 4 hours! Then she still goes to bed around 8pm.
I can't even keep track of Annabel's naps at all. I know she wakes up around 8am too and has a bottle and falls right back to sleep until around 11am! Then she eats and plays with Josh. Usually in the afternoon when I pick up the girls she is snoozing too but the second we get home she's wide awake from 4pm until I put her down to sleep around 8pm. This baby loves her sleep!