We’ve all been there. It’s pretty obvious because your nice new shiny chain is silly loud! It’ll only cost you one quick link (Shimano say theirs aren’t re-usable). I think KMC say theirs are re-usable IIRC (I’ve been using a used 11sp KMC quick link on the trainer with an 8 speed Shimano chain for months and it’s held up well anyway).
I have done that as well but caught it before I did a ride. One thing I always do now is back spin the crank after installing a chain. Seems like any install issues really present themselves on a back spin.
I find that I can reuse the Shimano ones about 3-4 times before they feel loose. I was going to buy the Connex link but it won’t last forever anyway because the roller portion wears like the regular chain anyway, so sticking to Shimano.
Also someone here noted that the chain being so slack in that gear combo is ok because “you shouldn’t be in that gear combo anyway” which I personally think is not the right approach to have for this. The chain should be the correct length, and if the argument for an extra long chain is that it will put less stress on the derailleur in the big/big combo, my retort would be “you shouldn’t be in that gear combo anyway”
Yeh, I definitely wouldn’t spend that much if I were re-using them all the time. But that is some good anecdotal info. I’m yet to decide whether to clean my new race chain on or off the bike (using Tru Tension drip race lube), so good to know the links hold up well.
You seem to be misunderstanding the advice above. The correct chain length has two variables and the advice varies depending on the rear derailleur used.
If the Rd is properly sized with enough capacity to take up all the slack in all combinations then you can size the chain longer than the big+big+2 sizing method and still not have slack in the small+small combo. So all gears work and you have less tension overall in all gears. No one afaik has suggested sizing the chain extra extra long like the op has done.
The second case is when using too short of a cage for the gearing combination chosen. In this case you have to decide if you size the chain using either the big+big+2 method which will result in a longer chain and the small+small combo having slack, or removing all the slack in the small+small resulting in a shorter chain. This will lead to the rear derailleur and/or hanger and chain stay blowing up if you accidentally shift into the big+big because the chain is too short.