To answer your question, it depends.
Some are, some aren't again, I hate to be vague, but it depends. Some amps are known to eat tubes quickly. Quality of build is another issue. Some amps are built very well using quality components, others are built very cheaply using crap components. There's a whole continuum.Originally Posted by Katastrophe
It depends on how many tubes are in the amp, and what types are in the amp. A fender Champ uses three tubes: 5Y3, a 6V6 and a 12AX7. Depending on whether you buy NOS, current production or a combination, it could cost as little as $30 ($10 each for new production) to a hundred dollars or more for rare NOS tubes. As a general rule, NOS tubes last much longer and sound better than current production tubes. Obviously, the more tubes an amp has, the more it will cost to replace them.Originally Posted by Katastrophe
As a rule, current production tubes (made in Slovakia, Russia and China) don't tend to last as long as NOS tubes made in the West (USA, Great Brittain, Germany, Netherlands). I've seen lots of old Fender amps with their original tubes.Originally Posted by Katastrophe
Usually when you notice the amp losing power, changing tonallity, etc. Keep in mind that it is a good idea to replace the tubes before they fail, sometimes there can be lots of collateral damage if a tube fails (takes out one of the transformers, etc.)Originally Posted by Katastrophe
The Rebel is kind of unique in that it uses two different sets of power tubes a pair of 6V6s and a pair of EL84s. Most amps in this wattage range only use one set of power tubes.Originally Posted by Katastrophe
Keep in mind that generally, you get what you pay for. Lots of times, inexpensive tube amps are built very cheaply with marginal components. But there are exceptions to this rule.Originally Posted by Katastrophe
Since you mentioned Egnater, I'd check out the new Tweaker. It seems to have a lot of features and offers tremendous bang for the buck.
There are lots of vintage amps out there, and while they sound good, they can be expensive.
As with most things, any tube amps will have its strengths and weaknesses.