I love changing photos and seeing everyone's new photos.  It does mean that I have to learn usernames more, but I think it's so fun!   I usually try to keep myself in the pic if I can, but sometimes I can't find one to match the month so I don't.  Overall, I think it's great to see other's personalities based on what hey choose every month.  I don't usually go looking at people's pictures on a regular basis, so changing the profile pic livens it up a bit.