Years ago, I used to swap around barrels quite a bit, but I'm down to just a few and tend to leave them set. I did some experimenting back then, and while a few tend to think of them as snake oil or a gimmick, I found that using hinge pins that minimize slop help return the POI to an acceptable level -- usually well within an inch at 100 yards of where it was previously.

No, all frame/barrels combos don't need them. And those who use brute force to hammer a pin into a frame are doing more harm than good. But used as intended and with a dedicated forend that is always tightened the same, those pins and the resulting solid lock-up do make a difference and remove much of the guesswork when swapping around barrels.

Switching buttstocks tends to create the greatest shift.