Vesp scarcely changes a character's appearance either. Especially if I've gone 'n gotten someone to draw them as a commission piece, request, gift art, etc. I'd rather not waste another's time drawin' a character that I may change altogether sooner on. My character's appearances are dead permanent less, like madam Suragaha stated, they receive a scar or somethin' minor of the sort. Otherwise, their skin is stuck.
The only times I ever changed a character of mine's flesh is when I completely re-did Creedance (for he was one of my noob characters till Vesp said, "ew. Revive this poor soul please and make him beautiful.") and when the user WanderBird was a doll 'n made Vespian a brand new preset/design scheme for Christmas a few years ago. The preset ye' all see him wearin' as of present.
Otherwise, I cannot recall thoroughly changin' a character's theme.