Much depends on how the battery is maintained. Under healthy conditions, batteries are rated for 800-1000 cycles. This may be reduced depending on the use and storage/care of the battery. Keep your battery charge level between 30-80% where possible. This will greatly increase the life use of your battery unit. Do not store your battery plugged into a charger. Charging should be monitored and the battery should not be left plugged into the charger.