How long should battery charges or rechargable batteries last?

[Jenga]

It's for my digital camera. I just noticed that the batteries are not holding power for very long like they used to. Only a week or two ago, I changed the batteries and they were flat in 10 minutes.

They are about two years old now and I have on average charged them up at least once a fortnight. I am not giving up with them yet but I suspect they are getting past it.

[rojash]

You haven't said what type of batteries (eg, NiCAD, Li-Ion, etc..)

[ACtheTROLL]

broadly work on 1000 charges
... nicad needs to be discharged to 10% before recharging
fully charge to store
LiLon and Nimh like to be discharged to 25% before recharging also stored at 25% of full.
(how you are supposed to determine this on a train is beyond me!!

but generally you can put them in a charger 1000 times....
(thats full charge or just topping up in case).
however .... 1200 charges in 8 months is better than 600 charges in 2 years ....

once they start to fail ... you can try putting them in the fridge to store them .... and a spell in the freezer could rejuvenatr them for a while.. (it could also split them .... so be careful