Originally Posted by Great Mind(s)
It's not like it's some official contract they sign or something... It would seem like the X-Men take who they can get. Wolverine became a team member after waking up in the mansion and stealing vehicles and insulting everyone.
i didn't know being an X-man was all in the uniform lol
wolverine left after X1 and only came back for his own reasons, and then in a X3 deleted scene they decided he left again