I've only had these batteries for about 2 weeks and they've exceeded expectation. I use a Sony ICD-P520 Voice Recorder everyday to record about 3 hours of lecture. I usually have to change out a pair of regular Alkaline Batteries after about 12 hours (4 days) of usage. These Eneloops have lasted just as long as Alkaline Batteries, maybe a little longer, WITH the additional aspect that they are rechargeable. Highly recommend these batteries for those who use AAA frequently; they will pay for themselves after a couple charges.UPDATE 12-18-2010Still using these batteries to this day, though not nearly as frequently. Compared to a pair of Energizers which I've had for the same amount of time, have seen less use, AND have since gone defective, I am very pleased with these Eneloop batteries.