Many tubes are rated for 10,000 hours. That's well over a year, if you never turn it off, so most likely you will get 3-5 years service from normal usage of 4-8 hours a day.
The main concern with tube equipment is heat, so don't use it inside an enclosed "entertainment center" cabinet.
One more word of caution. Long tube life depends on design margins. Some preamps are designed "on the edge" or beyond. I won't mention names... Just ask around...
The main concern with tube equipment is heat, so don't use it inside an enclosed "entertainment center" cabinet.
One more word of caution. Long tube life depends on design margins. Some preamps are designed "on the edge" or beyond. I won't mention names... Just ask around...