I'm no expert but I always thought driver tubes are not run very hard and should last like two or even three times as long when compared to the amp's output tubes (which run anywhere from 2000 to 6000 hours depending on how hard you drive them and their bias setting).
How long should Pre amp (12au7) tubes last in Rogue Preamp?
I've always heard Rogue equipment drives tubes hard. My RP-5 (purchased in OCT 2017) still sounds great with the stock JJ's. No distortion or any added noise. Typical life (in hours) of general 12au7's for a Rogue preamp? I may try the newer Gold Lions next time, although I am happy with the sound of the JJ's