In the first few months dd used to nap those big 4 hour stretches. Now I'm lucky if she does anything but catnap all day. She does still have days when she takes a nice long nap, like today, but for the most part she just naps for 15 min. here and there. I sure do miss those marathon naps.
We've never had a structure or schedule as far as naps are concerned and it has worked out well for us. I'm a big believer in following her cues. She sleeps and wakes whenever needs to. She usually sleeps well at night no matter what her naps were like during the day.