I'm an old time smoker that used to be able to smoke as much weed as I wanted, if I got too high, I got too high comfortably. But after a few years, I found that smoking large amounts of weed caused anxiety, racing thoughts, etc... Basically, getting really high isnt pleasant for me, which is very easy to do with todays strong herbs.
So, for me getting "stoned" has come to an end. I micro dose now, just a hit or two until I feel good---then I STOP ! Works for me.
Side note: I'm not alone, I know a lot of long time users with similar stories. I've also heard Cheech (or Chong not sure) mention that this happened to him as well, almost like developing an allergy to weed after long time use.