I regularly re-use quick links on our tandems and half bikes. I have only had one issue in over 50K miles which was the quick link opening up when the chain went slack (on a half bike) as described in the quoted link. I can say I had re-used this link a lot (I hot paraffin wax the chains about every 300 miles). Since that occurrence, I will replace the quick link when I can fully install it with my bare hands. If I need to brake the rear wheel and apply torque to the crank to get it to engage, I will continue to use it. The scenario in which this failure occurred was I was pedaling hard to gain speed at the bottom of a climb. As I hit the bottom, I downshifted quickly which outreached my ability to spin fast enough to continue to put power into the system and the chain went slack very quickly and opened up. There was enough time to un-clip and come to a stop. I don't see the likelihood of such a link opening when under force.

All that said, these have been all 10 speed chains. I will use the quick link that comes with the chain and will swap in a older quick link from a spent chain if it is still good.

I am about to upgrade one of the tandems to 11 speed and will be watching this as I gain familiarity with any peculiarities of an 11 speed drive train.