I didn't like doing it, because it was expensive, but I worked through my dealer and re-tubed via ARC for my VT-100 MkIII. I'm glad I did. In the process, they found a bias adjustment problem, and did a minor repair that will prevent unpleasant occurences in the future. Also, the end result sounded as good as new. (I think tube-rolling is kind of interesting, but, having blown up several tube amps over the years--which I've found to be ugly experiences--I leave the amps to the pros. Pre-amps and phono-pre's are a different story...)
Just my two cents.
Just my two cents.