I’ve known about it for some time, but never took the time to fully dial in with a chest monitor.
Like you, I’ve instead used the “can I carry on a normal conversation” as a rough guideline.
6-7 years in - so far, so good
I’m pretty sure on my “typical” (daily) hikes I'm occasionally bumping into some Zone 3 stuff with the steeper climbs. Still the vast majority of the hikes are in what I’m calling Zone 2.
I’ve thought about going to Bozeman and paying for a lab test and investing in a chest or arm monitor, but the fact is what I’m currently doing works.