^^ I guess I treat naps just like I do WBTB. I definitely only attempt WILD/DEILD during naps, though accidental DILD's have occurred many times. This is probably because REM is very likely during naps, and you never quite enter a deep enough sleep that would break up a WILD attempt and make DILD necessary.

Also, if I'm napping more than a few hours after waking, I don't bother at all. This may just be my experience, but it seems that, once my night's sleep is well behind me, my dreaming mind has no real interest in working with me. So naps more than three or four hours after waking just don't produce LD's. So if you're like me at all, it may be that you're taking many of your naps too late.

And yeah, if you get most of your success at times that are not napping, it could be that they're not right for you. It's all a matter of timing, and if you've got the timing down, then stick to it; no sense trying to produce LD's at times when your mind simply isn't into it!