Schmange: Maybe some older hardware stores have a tube tester. My father built one from a kit in the early 60's. He showed me how to test the tubes from the TV's he was repairing. How I wish I had that tester now.

Derek: Good luck with your new amp. If my experience with Fender amps is any indication, you'll get many years of enjoyable use. I wouldn't worry about replacing tubes for some time.