I'm not sure if the question is: "Do you wear a backpack while riding?" or "Do you bring a backpack for when you go on hikes along the way?"

I prefer nothing on my back when I ride, but if I have to wear a backpack I don't mind too much. (It reminds me of my college days, riding to class with my books in my backpack.) I wear a Camelbak when I'm going to be in a hot locale with infrequent water stops; otherwise not.

However, two of my most recent tours have taken me to Zion Canyon and Glacier National Park. I had to get out and hike in both of those beautiful places. In Glacier I took my camera, snack, etc. in my handlebar bag, which I carried because I hadn't brought the shoulder strap on tour. It wasn't good. In Zion I bought a cheap, little backpack in the grocery store ($9.99). It was much better, and it was light. Even though I had a little backpack at home, I couldn't see jetisoning my purchase after I left Zion, so I stuck it in with my load and carried it home. I've decided it's so light, and it was so nice to have, that from now on, when my tour takes me to a place where I might want to hike, I'm bringing it.