I recently had a failure of a SRAM PC-1. It was the snaplink that broke. My first thought was this is a millions and millions served chain and it was just a fluke. Now I wonder. Original installation of the chain was done by a PhD mechanical engineer who also has 45 years shop experience pitching in at his brother's LBS. And has built a good number of frames for top competition use. Pretty sure chain was installed correctly. Chain was used on fixed gear DL-1, two years, maybe 3000 miles. I had the original leftover link (just one, DL-1 has a long chainstay) and installed it the old way. The join looks good. The failure looked like plain metal fatigue. All the other bikes in the house are on vintage chain and it will stay that way. They don't make 'em like they used to.