I can't afford (read: unwilling at this time to pay for) a custom frame. So. i buy off the shelf starting with the usual frame size/ standover "fit".

I have had a general bike fit at the shop for 50.00 which was setting seat height and reach. I bought a stem. Months later I've fiddled with the seat enough, I'm pretty much dialed in on my dual sport.

I had a "pro" fit done on my road bike for 100.00. Measurements taken, logged, shims added, knees tracked, the whole shebang. Still had to try different stems and fiddle with the seat. I still need to go back to compact handlebars. That last one was my mistake when i bought the bike I went to a deeper drop bigger bar. Shoulda tried it first. THESE measurements are on file at the fitters.

My fat bike is technically too big as it didn't come in the correct "standover height". I set the saddle, dug through my stems, found a better one, but still not enough rise. Bought a riser bar. Pretty much dialed in now. I may need to tweak when I put clipless pedals on it.

The old rigid mtb I bought, is technically too small. Yet it didn't feel "wrong". I can't explain this. Usually I hate a too small feeling. It has a quill stem and I'm almost out of seat stem, but still safe. I raised the saddle, brought the stem up about an inch and put clipless oon it. Last night I took it for it's first serious ride. Other than too much pressure on the nethers, it was amazingly comfy. And it turned out to be a damn fast roller that I can storm a hill on.

I am in no way "limber".

To recap, I have four bikes all differing geometries. Two I fit myself, two I've had fit. One is actually on paper somewhere. I dunno.
I suppose the real litmus test is can I ride all the bikes for the same duration?