So about 18 Months ago I got that very inexpensive Wasabi branded two battery and a travel charger package from Amazon for my K-5. The batteries worked well until a couple of months ago one of them stopped holding a charge. Then last week the other one followed suit. So it seems with my usage (constant) they last about 1.5 years. For the money that still seems reasonable, but for comparison my OEM K-5 battery is still working well. I just thought I'd update what I had said before which was that these were good batteries. I still believe that but maybe they aren't quite as good as the OEM ones.