This is a good question that most of us run into.
What I did (and this is for working brass only not loading the case) was to put one of my older computers on the bench which I also keep load data. It’s hooked up to an internet movie supplier and watch movies as I load.
Also every half hour or so, get up, stretch and walk around.
What has helped me the most is a good chair. I have a very good leather office chair that I bought used at a store that specializes in office equipment. This allows me to change the height of the seat and other portions of the chair. I paid $130 for it and I have seen the like for over 700$.
I have recently done one process (Size) 500 new cases in one session.
At my age <60 but close, I have been thinking about finding a pneumatic or electric press that takes the fatigue off the shoulder and arm. But don’t know of any.
It was a sad day when I discovered my universal remote control did not in fact control the universe.
Did you hear about the latest study.....5 out of 6 liberals say that Russian Roulette is safe.