I tend to forget when exactly I change chains and cassttes, but lookig at this thread my KMC X8 has lasted about a year - that chain is showing 1% wear, which might mean it'll snap in use, especially now I've increased the controller limit by 3A to 18A. So, I've just now ordered another from Amazon directly (dispatched and sold by Amazon), which turned out to be a strange process... because the Amazon website kept recommending a seller with only a 88% positive rating above their own listing. Amazon's own price was £12, the crappy seller's was £15.80 (dispatched by Amazon but sold by the crappy seller)... and before I added Amazon's X8 to my basket, it stated a delivery time of over a week for it's X8, but after payment it promised a delivery date before Wednesday, plus it gave me 40p off something else for no reason I could see. Fearing I'd been signed up to Prime somehow via one of Amazon's Dark Patterns, I removed that food item from the basket (also made sure I hadn't been subscribed for a monthly delivery, through another Dark Pattern), and the 40p discount was applied again. Er... thanks? Amazon don't seem to be pushing items they sell themselves anymore. Another example is SSDs that they sell themselves. It's preferable to buy "dispatched and sold by Amazon", because they're less likely to be fake, grey market factory rejectss, retuned items sold as new etc. Anyway, I've finally last night replaced the old cassette, with the new one bought in Feb this year. The newish chain did sortof wear into the old cassette, but not as well as I'd hoped. In warmer weather matters improved, but in my case the chain needed replacing before enough progress was made - it only slipped every so often on a couple of gears (the ones I use most), wasn't too annoying.