The character looks I've grown to prefer:
Trevor: Mullet, Handlebar mustache (which is misnamed and actually a horseshoe mustache, as it does not have graspable appendages), aviators, filthy white t-shirt, camo pants, military boots.
Michael - Bald, clean shaven, wearing anything that looks expensive.
Franklin - Big afro, big beard
I haven't bothered change Franklin or Michael's clothes in a long time, since they're civilized human beings who apparently shower and change clothes regularly anyway.
As far as I can tell, this does not apply to Trevor.