Question about valves running hours


I'm new to the tubes world and when I bought my amplifier the seller told me not to run it for more than 8 hours, letting it for rest a couple hours before the next listening session. I wasn't told why, but now I got curious and I want to know more about it. 
What's the reason for this limitation? What can we damage and why?
128x128migueca

Showing 1 response by oddiofyl

If the amp is biased correctly it can play long periods of time without issue.  I listen to my amps for hours , I do turn them off when I go out though, but cycling the power for short periods actually shortens tube life