How often do you have to change your tubes in your tube amp?

When it doesn't work any more any more. And if if a tube is going bad, haw can you tell the difference, since tube amps make so much distortion anyway?How often do you have to change your tubes in your tube amp?
usually once a year. While I was on the road on a regular basis I changed them more due to wear and tear of loading and unloading. I used to get a high pitched ring and a loss of sustain. I have a Boogie. I use either Groove Tubes JJ's. Tubes take about a month to really break in.How often do you have to change your tubes in your tube amp?
once a year
Main power tubes like EL-34, KT-88 and KT-90 are usually good for 2,000 hours of play time.



The real answer is when they no longer function properly, i.e. sound right, no longer hold bias, develop a hum, etc.



A lot depends on your useage and the amp itself, there are lots of sites deadicated to audio and most have sections on tubes