Very few companies sell locally made tubed equipment. Those that do will have spare tubes for replacement. Won't be cheap I guess.
If you bring back tubed equipment from abroad , you should bring back spares with you or ask someone to do so if you are already here.
Typically power tubes can last 1,000 to 2000 hours ( of actual use ) and small signal tubes can last up to 5,000 to 10,000 hours ( of actual use ).
BUT tubes CAN break down sometimes with broken tube heaters or internal shorts due to physical abuse ( while shipping ?). Even powering them up and down several times stresses the heaters and they can fail prematurely. Proper design can minimise such heater failure.
Locally available NOS tubes from BEL are typically not as good as those we get from overseas. I bought a lot of them over the years and many had very poorly matched sections in dual triodes. They were cheap at the time and I found, so was the performance ! Especially the Russian tubes that the defense forces used . Most had Bakelite bases that were loose and many tubes were 'slightly tilted'! Poor assembly I guess and the defence dept. bought them ! Maybe just bought junk and not for real use ! Who knows !
Get some good tubes as spares now , even from Ebay. Don't wait for them to break down. You never know when you might need them....of if you are lucky , you may not. But then tubes do age. They loose their amplification capability which affect a whole lot of other parameters. Maybe a tube set change 'might ' improve things after 5/10 years ? Maybe !
