Your laptop’s battery life can be extended if you take precautions to avoid frequent total discharges. One step you can take is to set up alerts so you’ll know to plug in the power adapter when the battery goes down to a particular level.
Almost all laptops display alerts if the battery has 5% or 10% of the charge left. You can easily modify your notifications to avoid total discharges.
In Windows 7, click on your battery icon in the system tray and select More power options, then select Change plan settings -> Change advanced power settings and change the low level battery setting to 30% and the critical level battery setting to 25%.
It is also recommended to keep the battery in cool temperatures to make battery life last longer.
Additionally, if you are planning not to use your laptop for a long time (for example when you go on vacation), make sure it is charged about 40% before you unplug the power adapter and power down.