I've replaced two of mine so far - Tung Sol 12AX7 into V1 (original tested as 'worn'), bargain eBay 60s Brimar 12AU7 into V3 (original tested as 5hite).
I've resisted the temptation to upgrade the power tubes, I'll get my money's worth out of the Ruby Tubes first. If anything dies on a gig I'll whip out my spare amp rather than mess around changing valves!
I stopped buying from Watford valves after they sent me a valve in just an envelope. That's right, a valve in its little cardboard box, in an ordinary paper envelope - no bubble wrap, no jiffy bag. Fair enough it survived the journey, no thanks to Watford Valves.
Also that Cryogenic treatment is the worst kind of nonsense.