All things considered, keeping tabs on ZZ Top is pretty simple -- their lineup hasn't changed in decades, and neither has their distinctive brand of Texas boogie rock. But that doesn't mean ZZ lore doesn't contain its share of little-known facts, and we cover some of the most interesting in this edition of You Think You Know Classic Rock?

Even if it seems like guitarist Billy Gibbons and bassist Dusty Hill have always had their distinctive long beards -- and that drummer Frank Beard is the only member of the band who doesn't have inches of growth dangling from his chin -- most fans understand that at one point, the guys sported a different look. So when did they make the change, how did it happen and how much money did they turn down when Gillette tried to persuade them to shave it all off? It's all right here in the video.

Hit "play" and you'll also hear the real-life story behind the 'Deguello' track 'Manic Mechanic,' as well as where you can turn to find guitar picks that will help you duplicate Gibbons' signature sound (hint: It isn't as simple as a trip to the store). And that's not all -- we'll also fill you in on the set list change the band members were forced to make after one of their better-loved songs kept getting them injured in concert. You think you know ZZ Top? Here's your chance to find out.

Watch ZZ Top Tear Into 'Waiting on a Bus' at Montreux

See Yearbook Photos of ZZ Top's Billy Gibbons and Other Rock Stars