Replace tubes yearly?

I just watched a Paul McGowan video (PS Audio) about the wisdom of leaving your gear powered on all the time. I get that. He also said that vacuum tube gear is the exception and not to leave it on all the time. I get that too.

But he also mentioned that it didn’t make a huge difference since you probably should replace your tubes every year.

Is that true? I have an Audio Research LS-16 tube preamp from the late 90s or early 2000s. I don’t think the tubes have ever been changed. I’m not really a ’tube’ guy but this unit was given to me 6 or 8 years ago. As far as I know these tubes are original.

At one point I got curious about the different sound quality potential of different tubes and another Audiogon member lent me a set of tubes to try out. I could definitely tell a difference but did not think the new ones sounded better than the original ones. I mention this because at that time the original tubes were quite old and still sounded quite good. And still do.

So, bottom line is, is there any real need to replace tubes on a schedule of some sort. Maybe its different if it is an amp versus a pre-amp?