Have only had it a few days. Seems to work very well. I was a bit surprised at how fast it charges the batteries (less than a couple hours for a fully discharged AA ). It's my understanding that fast charging can shorten battery life. I have some other chargers that will not recondition batteries like this one will and those will take overnight to fully recharge a AA battery. I will continue to use those chargers when I am not in a hurry.