Hmmm. depends on genre. Is it a coincidence that many of the jazz greats sported short hair or bald pates and facial hair. Joe Pass, Django and Wes Montgomery all had similar moustache designs. Modern virtuosos Martin Taylor, John Scofield and Charlie Hunter all have goatees. Al di Meola was at his best when bearded.

In the areas of bluegrass, country and I'd say facial hair is almost compulsory to whit Clarence White, Martin Simpson, Tony Rice, Jerry Donahue..

Someone here reckon Satch lost it when he went for the Agassi look. I reckon the excellent 'Crystal Planet' proves otherwise. On the subject of which, does Tom Morello have a shaved head? In his pictures he usually has that Mao cap on.

As for pot? probably a useful accessory.