Seven years! I hadn’t realized I had purchased my Bose QuietComfort 25s over seven years ago. Three or so weeks ago, my left speaker just quit working. I have three cables, one with an in-line mic, that all have the same symptom, so I’m positive it’s not the cable itself. I’ll crack it open and start hitting it up with the multi-meter later this week, but 7 years is not a bad stretch!