I'm either VERY LUCKY or an anomaly. I have 3 tube amps and 2 tube preamps (McIntosh MC-225 paired with an Audio Research SP17, a Dennis Had Inspire "Fire Bottle" 45 paired with a Dennis Had LP3.1, and a Reisong A10 EL34 Integrated). The stock Reisong tubes were replaced in 2018 with NOS tubes, the Dennis Had gear has Emission Labs 45 tubes I installed in 2018, the ARC tubes are more than 10 years old (I bought it in 2020 from the original owner and he had receipts where he replaced the tubes in 2012) and the McIntosh has Westinghouse 7591 "Made For McIntosh" tubes that appear to be original based on my research (I bought it from the original owner in 2021 who bought it in 1963, my year of birth -- he said he had never replaced the tubes and the technician I had go over it said all tubes looked original, it had been in storage for 20 years).
Each system gets played several times a week, for an hour or two each session. For those of you with far more knowledge than I have...what am I doing right?? I'm not complaining, far from it. But how can the OP go through tubes as he said and I have Dorian Gray tubes??