Kool Tools: Battery Guardian
To get the most out of a MacBook battery, it should be depleted once a month. Depleting involves disconnecting the mains power and using the battery until the charge is nearly empty. However, few of us remember to do this.
Enter Battery Guardian from DssW (http://www.dssw.co.uk/batteryguardian/), a nifty -- and free -- tool that will help you extend the life of your laptop's pricey battery. It works by placing a small heart in the top-right of the Mac OS X menu bar. When the time comes to deplete, the heart turns red.
Once started, Battery Guardian -- which requires Mac OS X 10.6.8 or higher -- runs in the background and doesn't require the application to be left running. It will automatically track the battery charge. Each time the battery is depleted, Battery Guardian will reset the reminder.
Hey, it couldn't be any simpler than that. And your battery will thank you.