Audio Research - should I replace the valves?

I've owned and steadily enjoyed a McIntosh MC275 tube amp and C2600 tube preamp since late 2017.  I've never tried to estimate the cumulative hrs. of listening, but it's up there.  I purchased a complete replacement set of replacement tubes for both components from McIntosh a couple of years ago, and stored them away for eventual replacement. I don't recall seeing any bias adjustments and frankly didn't know it was a thing.  I suppose it's time to swap them out!

@rickisme  , I just did a cursory search & I am picking up that the newer 275s are self biasing.  Other wise, occasional checking & adjusting the bias of output tubes is a MUST.  Especially after installing a new set.  Your owners manual should clarify that for you.

@ghdprentice upscale audio quite ("paused") sellin tubes this past april. 

@cey  , when was the last time you checked?  Uncle Kevin has been selling tubes again for a while now. 

hey there @immatthewj thanks for catchin that so quick!

i just re-read my emails and revisited the website. im mistaken.

seems even tho theyre sellin tubes again they never took down their "we paused out tube selling" page. 

thank you my friend

No sweat, @cey  .

anyway, the last time I bought output tubes was a couple of years ago; I bought a dozen of the reissued Tungsol EL34s from Jim McShane to replace a dozen of the reissued Mullards that I bought from Uncle Kevin that didn't last very long.

I am a big fan of Jim McShane now. 

"

No sweat, @cey .

anyway, the last time I bought output tubes was a couple of years ago; I bought a dozen of the reissued Tungsol EL34s from Jim McShane to replace a dozen of the reissued Mullards that I bought from Uncle Kevin that didn’t last very long.

I am a big fan of Jim McShane now. "

@immatthewj holy smoke i heard about new production longetivity issues, but man that sucks. i gotta say ive had no such problems, but i hear aout em plenty. been runnin new production tubes not-so-gently in my guitar amps for a long time with very few surprises, tho i think thats in the power section. funny i never paid no mind to tube selection til i started getting into hifi. always told my tech, hey, whatever makes it sound good. and it always sounded good.

also, both jim and kevin are known for testing the heck outta them. andy, i think, puts em thru the ringer as well, tho he doesnt do new production.