When out riding geared bikes I take a spare powerlink with me in case of breaking a link etc.
But for my SS/IGH bikes a single link won't necessarily work.
Do folk just take a few chain links out in their packs?
You can get power links for single speed chains , but it's a gamble that it'll be an outer link that breaks cleanly.
I carry a 4 link section of chain and obviously a chain tool.
We all use KMC Z610s chains & have NEVER had a failure.
I'm nearly 16 stone & fairly high mileage.
At £12 odd a pop , it's no big spend to change my chain every 6 months to be on the safe side , decent stainless steel sprocket & chain wheel will take a few chains.
Yes - got the one small pouch with 9sp powerlinks and a few links of 3/32" chain and a 3/32" connector and a chain tool. Don't bother editing it for different bikes - just grab it and shove it in a jersey pocket regardless of bike.