What I do is buy two sets of tubes for my pre-amp --- using one set as if they were my only tubes and the other as back-ups and to test for the degradation of my primary set of tubes. After about a year, I swapped out the tubes that were in for a year for the other set (that were the same type & stock and had maybe 10 hours on them). I played with the second set for a week and determined that the 1st set with a year on them sounded the same. So I put the 1st set back in and played them another year.
At the year 2 mark I tried again the back up set and realized that my 1st set (with 2 years on them) sounded a little grainier and had a little more noise and did not sound as "lively." So... I deemed the 1st set to have lived the life out and trashed them. My back-up tubes then became my primary tubes and I buy a new back-up set.
A side note... I have had tubes blow on my power amp and cause much damage. I have entirely gone away from tube amps and do tube preamp w/SS amp.
Finally... tube rolling --- if you have the $ and the time to play around can be anything from fun and advantageous to kind of a waste of time.
At the year 2 mark I tried again the back up set and realized that my 1st set (with 2 years on them) sounded a little grainier and had a little more noise and did not sound as "lively." So... I deemed the 1st set to have lived the life out and trashed them. My back-up tubes then became my primary tubes and I buy a new back-up set.
A side note... I have had tubes blow on my power amp and cause much damage. I have entirely gone away from tube amps and do tube preamp w/SS amp.
Finally... tube rolling --- if you have the $ and the time to play around can be anything from fun and advantageous to kind of a waste of time.