I got around 3500 hours out of mine, but replacement was noticeably better (purchased from Kevin Deal).
Life of KT150 tubes on ARC Amps
I have Audio Research 250SE amps and the tubes in it have 2400 Hours. I wanted to hear experience from other ARC users if they replaced KT150 tubes before 3000 Hours. I am not sure if i need to replace them now or wait for some more time. I dont have new set of tubes for me to compare with my current tubes and wanted to hear from other people who replaced the tubes.