Replace tubes yearly?

I agree that the answer is no, but as a tube enthusiast, I always have back up tubes and periodically switch out tubes to compare the old with the new to make sure everything is in top order. This takes organization and good notes to keep straight.

My audio research vm-220 has 12 tubes (8 x 6550) per mono block, but still sound glorious when manually biased. Pre-covid it was $1600 to replace all my 6550s (16 or matched octet) by audio research. Only had to do this once in 20 years. But with the California heat, I have now switched over the Aesthetix amps (I bi-amp Atlas monos & stereo amps in my small room and only need to consider one power tube per channel. Much simpler and a lot less heat while enjoying the sound year round.

For those interested in learning more: The www.audiophilefoundation.org recently had a zoom discussion on tube testing with a known expert and offered best practices. Which tube tester and which areas to check to look for with tubes make a a big difference. Members can go to the website and look at past events to watch the zoom (cost is $30 annually gets you lots of other benefits too).

I think the tone of the 6SN7 tube is naturally full and warm. The Ken-Rad VT231 has the most solid bass, while the RCA or CBS Hytron 5692 has the smoothest sound. Overall, in my Cary SLP05 and Schiit Freya+ and Saga I like the Raytheon VT231 for best overall sound. But lots of good ones. Best from WW2 VT231, JAN 6SN7 from 1950’s, and 5692. Just my experience- these all seem very reliable.

Amplitrex AT1000 is the tube tester to buy.

https://amplitrex.com

Tests multiple variables on most audio tubes.

As OP I have nothing to add to the great technical advice given in this thread.

I do wish I could remember which Audiogon member sent me those tubes a few years ago. It was a very gracious, and trusting, thing to do for someone he’d never met anywhere but here.

I will also say that in the last year or so I get a little bit of speaker hum when I first turn my system on. It goes away to complete silence after about 5 minutes. This is an old system so I guess it could be anything but it makes me wonder if it might be a tube. I may get a back-up set just to test it.

But, I confess that I absolutely hate messing with my system, fooling with cords and pulling components out. I guess some people enjoy that but I don't.

I have, and like, the Amplitrex tester.  It is simple to use, tests at full power so the tubes are measured under stress, and it displays both test measurements and the specified values to compare the results to.  But, one still needs experience to know what the results mean as to whether or not the tube needs replacement.  The biggest downside to this unit is that it is expensive.  There are kits for testers that experienced tube professionals like.  One expert who owns well north of a dozen testers, including several Amplitrexes said that his favorite is the kit called the e-Tracer out of Taiwan.  Hooked up to a laptop, it will curve trace the tube (the Amplitrex can do that too).