Tube Replacements for SF Line 3?

I recently bought a used Sonic Frontiers Line 3 and am really enjoying the sound. I'm now wondering what tube upgrades (if any) I should consider for the preamp. Also, having not used any tube-based unit before, how long can I expect the tubes to last and should I consider keeping replacements on hand in the eventual event of some of the tubes failing? Finally, is it OK for me to keep powering up and powering down the preamp every day, or do I really have to leave it on stand-by. (I have the unit hooked up to my PS Audio 300 powerplant, which I really like to turn off when I'm not around because it seems to double as a home heating system.) Thanks in advance for any advice on what may be stupid questions :-)
Hi Outlier; I have faced this question with a SF Line 2. I like the stock 6922 Sovteks pretty well, but the Valvos (from SF) are smoother, sweeter, a bit warmer and more tube-like. I tried an exotic set of tubes from Upscale Audio in LA: Amperex 7308s in the forward positions, but got a really un-natural, big, bloomy, soundstage that I didn't like. Still, I'd recommend Kevin Deal at Upscale as an expert on SF tube equipment. He's at Just explain to him what kind of sound you want. Good Luck. Craig.
Outlier; also, those aren't stupid questions-- many of us have "been there", and I'm still working on it. Craig
Thanks Garfish for the advice. I think I might get some Valvos soon. I hear that that's what the new SE edition will be coming out with as well. Cheers,
I tried the NOS Amperex 7308 and Phillips ECF82 from Upscale in my Line 3. This combination had much better tonal color then the stock Sovteks, but they were a bit soft in the extremes for my taste, and had less overall resolution and control. Kevin recommended NOS 6H23s as an alternative, but I haven't tried them. Does anyone know anything about the new Sovtek 6922 PI? I'm not sure they're even available yet.