+1
I am not in the geek camp. I have all tube gear. My equipment has tube time counters. Even if they didn’t it isn’t that hard to generally estimate the tube time. I have about 40 tubes in my system. I have swapped 3 tubes in the last 3,000 hours of play… they are recommended to be replaces every 2,000 hours.
I just buy tube sets either from the equipment manufacturer or Upscale or the Tube Company. I keep an extra set for each unit. If you get a whistle or strange effect. Swap to new tube set a couple at a time to ID bad tube. This has only happened to me twice in ten years. Really simple.