I don't use models but...

Sometimes I set up my camera to take pictures of myself so that I can better get a sense of how a body (or hands or that angle on a face) looks.
I sometimes just need a basic idea and then I translate that to whatever my character looks like. I often adjust it a bit too like the photo below, where my character didn't end up having both hands on his knee.
I don't do this for every drawing by any means, but it's fun to compare the photos to the final sketches when I do use my silly self portraits.


BONUS:
A stupid but related personal story that's at least slightly amusing.

For an illustration of a dancing Angel, I once took photos of myself leaping up in a semi-dance, sometimes twisted, sometimes not. I must have taken 25 photos of myself before I got a sense of the movement enough to draw the angel dancing. Dance party in the studio! In the meanwhile my mother-in-law was watching my son downstairs in our very old house where you definitely would notice if someone was leaping around on the upper floor. Later she confessed to wondering what kind of "work" required so much jumping.