SmartSleep is great for those who are constantly on the go, opening and closing their Macbook. SmartSleep gives the user great control over how and when the computer sleeps and hibernates.
Typically, you’ll probably want your Macbook to sleep when you close it (keep the contents of open files and apps that are running in RAM). Sleep is conveniently fast. If you’re a student like me, you don’t want to have to worry about corrupting your hardrive after throwing your laptop in a bag of some sort and running around campus or dropping it on the floor.
However, what if the batter charge is less than 10%? If you sleep your Macbook and the battery dies, you will lose anything stored in RAM that wasn’t previously saved to your hardrive. Thus, you’ll want to hibernate. But keeping track of the battery charge and changing this setting manually is cumbersome. This is where SmartSleep excels. You can set your computer to sleep until it reaches a certain charge level (e.g. 10%), at which point it will hibernate to protect your data in the event your battery dies.
Another nice thing about SmartSleep is it just sits in your preference pane; no extra menubar icons necessary.
If you don’t want to pay for the new version, I’d suggest downloading the older, free version from Softsonic.