I’m sure that this is a much discussed topic with a range of opinions. I have had a pair of BHK mono amps and the BHK preamp for a few years and have never changed the tubes.
Two questions:
Should I change them?
If so, what should I replace them with? I know PS Audio sells replacements - are those the ones to get or are there others that people really love?
I think the recommendations is once a year or every 10,000 hours I thought I heard or read that somewhere on the forums. As far as what tubes? Like what RonP said tube rolling thread and a couple days to read it.