Connex are 100% reusable.
KMC links with an R at the end of the model were said to be re-usuable a handful of times, but I no longer see that limit in the instructions: Re-use as much as you want.

SRAM and Shimano say you shouldn't reuse them after they are opened. The issue is that the tab that locks them together wears out. In reality, I know of literally hundreds of Shimano and SRAM quick links that have been opened and closed several times without accidental openings, so it seems like a non-issue. But KMC makes it really easy and cheap to buy reusable links, so it is easy to play it safe.


A fellow mechanic used to save the leftover sections of 11 speed Ultegra chain from customer installs and their old quick links. Then he'd build himself new chains for his MTB out of these scraps - 8 sections of short chain and 8 used Shimano quick links. No problems.