Derek's stubble is clearly very well-maintained, which seems odd, considering he's apparently been living in the burned-out wreck of his old house and then in the rusted-out wreck of an old train depot. So where does he shave? Gas station bathroom? Does he have a plug-in for his car? Secret apartment/motel room somewhere? Is it just natural werewolfy hair secrets?
With a question this deep and well thought out I’m slightly embarrassed to say “I have no idea.” Sorrrrrry.