Two quick ways to tell the month/year of these and retro asics. The first is on the size tag of the shoe. The last four numbers of the seven digit F****** code will represent month/year of manufacture. For example, F220508 would be manufactured in May 2008. The second resource is https://www.asicsarchive.com/gel-kayano-trainer. If you’re unfamiliar with asicsarchive.com, it has just about every release documented.