You and me both.
Not too many years after that nightmare, I was perfectly capable of enjoying thru-hiking, carrrying exactly same weight anyone else would have been, moving at same speed on rough terrain, etc. Still couldn’t run a mile - or much shorter distances - in my wildest dreams. Didn’t matter, I was in exactly the shape I wanted to be in, for the things I cared about.
Can’t do it anymore, my body widely conspired against me in various ways, but glad I was capable of it and have the memories. If I had been able to run a mile, but not hike any distance with weight, I’d be alot less happy about what I had achieved at that point.
I’ve never heard them be interchangeable. Grew up in the NE US, PA, NY, FL, and MA.
I’ve spent most of the last twenty years in the Midwest, and can’t think of a single example.
The outlier would be very, very careful instructions - likely written - organized in an if/then fashion which is a totally different use case:
“Since” wouldn’t fit, at least without changing the instructions after the ellipsis.
And of course the classic example: “since you are up, get me a beer…” also doesn’t really work. (Apologies to some long irrelevant redneck comedian for ripping that off to make a point).
I’m trying in my head to make it fit in both casual and formal conversation, and it just won’t as far as I can tell.
Would love a counterfactual where both work!