is using a tube amp every day bad?

@bigkidz nope.

It's probably junk by now.  I'll send you $20 and a FedEx tag for it ;-}

My Fender tubes are now 10 years old and no problems, so rock on. The one thing that does kill tubes early is throwing them in and out of vans and gigs. If the amp just sits in the same place, the tubes will last years and the amp will only go up in value. 

It's not a bad idea to have an extra set of tubes on hand.  At various points you can insert the new tubes especially in the critical positions and see if you have been missing something.  My brother has vintage fender and marshal amps and just recently discovered that his fender was getting a little tired with the current tubes after he did some swapping.  Sometimes it happens so slowly that you don't really notice it.