Some of those here have avatars which never change.
Some change avatars now and again.
Some of us have never had an avatar.
So, do whatever makes you happy.
Some time ago I came across a photo of me at work, taken by a colleague. It later occured to me that it would make a good avator and put a face to the name. (Or at least the face as it was in 1985 !). But since then the photo has gone into that special place where inanimate object hide until you are no longer looking for them.
JimB