Well, you do amazing headshots. And a lot of folks would love a nice avatar. ^^ I don't know the time invested, but look at it from a few aspects.

1.) What makes you the most coin? Can you get 5 headshots for 50, and complete them in about the same time as 2 full pictures at 100 each? If so, then you've made more with headshots. :) (those prices are just made up.)

2.) What makes you happier to draw? If you are getting bored of them, take other things. Ultimately it is what makes you happy that should be done, money aside.

The reason is because I think people are getting bored to see to much heads, and me a bit too. I wish improve more my drawing anatomy, clothes, poses and background too.

Thank you very much for the help ^^

Take some time off and draw some personal art.