AA Batteries usually have 3 measures of life which are shelf life, Run-time and cycle life. Also, different types of battery chemistry have a measure.

Measures

Shelf Life: How long the batteries will hold their charge while they are being unused refers to Shelf Life. But in the case of rechargeable batteries, Shelf Life refers to the time the battery can hold its charge or before it needs to get recharged to offer its service.  

Shelf Life depends on the environment of a place. If your storage environment is warm and humid, then the Shelf Life of a battery will become short. The quality of a battery also affects its Shelf Life. The higher is the quality of a battery, the better the service.

Run Time: Run Time usually refers to how long a battery can run on single-use. Run Time of an AA battery depends on the device where it is being used. AA batteries are mainly used in digital cameras or flashlights etc. Each of these devices draws a different amount of energy. Because it is usually unknown how much energy is drawn by a particular device, so answering the lifespan of a battery on this point is quite tough.

Cycle Life: Cycle life usually refers to how many charges and discharges a rechargeable AA battery requires before it stops holding the charge. If one discharges a battery to 50% and recharges it to 100%, then it will be counted as a ¬Ĺ life cycle. Same as the Shelf Life, a battery‚Äôs cycle life also depends on the quality of it.