I mean.... I replace the tubes in my amps I play regularly maybe once a year. In my EL34 amps I just run JJ's and they're like $15-$20 ea? So $80 a year in power tubes. Who are you saving them for? I totally get the reluctance, as I have a lot of mechanical sympathy for my gear, but I don't sweat running stuff at 50-60%. Tubes are like brake pads on a car.