I got mine Dec. 2016, and have experienced odd charging issues. I recently cleaned them thoroughly with Q-tips and alcohol. Make sure all surfaces are clean, including deep inside the charging case. There are little electrical connectors down there.
I sweat on mine a lot - is there a build-up of salt? IDK. It's too soon to tell if the cleaning will work, but it can't hurt. My feeling, without being scientific, is that it's better now after several days since no weird charging issues, but still a bit too early to know for sure.
The stems press right up against my sweaty, salty, face. Then I drop them in the case. There's no way salt isn't building up down there. From now on, I'm going to wipe the pods clean after a workout, before I drop them in case, and I'm going to do a thorough clean once per week.
I think I'll sell these as soon as the new ones come out. Be very honest about their age. I'll get a new pair every two years and sell the old ones for about 40% what I paid (if I can).
If you sell them for $70 after two years, that's a cost of ownership of $3.75 per month. If you get $50 for them, that's about $4.60 per month. Well worth it for me. Of course they sell more for that used on eBay right now. But, frankly I would never buy these used at all for any price. Who knows what the batteries will do and the cost of replacing pieces is expensive. Seriously, I'd be afraid an eBay buyer would complain later that it was sold, "not as advertised" and cause issues, the first time they get any weird charging or connection issues.
I'd say just keep the old set so if you lose a bud from the new set you can at least use the older one, but will it work with new chipsets? I doubt it.
I may just keep them after buying a new updated pair, soon, in case I lose the whole new set.
