So when do you know if it's time for a new one? I've had mine (XT shimano) for about a year and just this week I've noticed that under hard acceleration my chain will want to pop out of gear and then go back in. I've tried adjusting my derailleur, but every time I really lay down the chicken leg power it will pop-pedal-pop :mumble: So I'm thinking it's time for a new one. Yes? No? Anybody have a favorite road cassette that they might recommend me giving a try?