Originally Posted by dsbrantjr

I consider that the "one use" constitutes "use on one chain" and toss the link with the worn-out chain. You should never close a modern chain by pushing back a pin. The pins are peened-over and you shear off the peened area when you push it out, as well as enlarging the hole. So always close the chain with a master link or (not my choice) the Shimano special joining pin which is sized to fit correctly in the enlarged hole. People have gotten away with pushing pins back but it is a less than safe and satisfactory practice.