Guess it just depends. Historically at least several hundred yards apart, but this season I helped dad move a ladder into the swamp facing one direction, and he moved one of his climbers probably 50-75yrds from it, if even that far to hunt the wind if the ladder wasn’t right for it.
But for semi-permanent stands, I’d say the couple hundred yard guidance still applies.
I have 3 stands on 40 acres. 1 shooting house on a big food plot, 1 tripod on a food plot, 1 ladder on power line. All around 200 yards apart. Not within sight of each other. Usually hunt 2 at a time with my son, sometimes all 3 if we take a guest.
Archery only for me so there are usually stands that are in close proximity of one another basically for hunting same edge, travel route etc with different winds!