I bought a multi-charger and four of these AAA batteries for use in a digital voice recorder. The Sony recorder takes two AAA batteries and I use it for whole day training sessions, so it's often recording for six hours a day, several days running. However, there may then be a spell of some weeks when it's not required, only to be needed again at a moment's notice. For this reason I need batteries that will not only perform well, but will hold their charge if not used for a while. After looking at all the ones available and comparing reviews and prices I chose these "StayCharged" ones from Duracell, and I'm pleased that I did.
As I want to start the voice recorder at the beginning of each 3-hour session, and don't want to have to keep checking it throughout, I change batteries before they are fully discharged, but would estimate that for each full charge two would certainly provide 10 continuous hours of recording, maybe more, which I feel is pretty good going for two small batteries. I always keep two fully charged spares in my bag and whenever the battery meter gets down to about one third remaining, I simply swop them over, and re-charge the spent pair overnight.
I've always used Duracell batteries, but never rechargeable ones before now, and I'm so pleased with the performance of these, I'm buying some more to use in other devices!