Experienced golfers just look and know. Their ability to judge distances can be eerie.
Cool. Now let's relate that to photography, which is what this is all about, after all.
You bill yourself as an experienced photographer. Can you just look at a scene and say, "that tree is 200' away. At f/3.5 at 55mm on this full frame camera, if I want to put that tree at the furthest end of my acceptable DOF, I'll need to focus at 64', which is riiiiight.... there. Click."
I've been shooting for over 40 years, and certainly call myself "experienced", but I freely admit that I certainly can't do it, and don't personally know any photographers who can.