Use Sleep mode only if you intend to take a two-hour break or less, because sleep mode uses a very small amount of battery power. Windows and Mac OS offer Sleep mode as a way to save energy and prolong the life of the laptop's battery and what is more important, it saves all the things you've been working on. When people use their computers for hours and decide to take a break, they leave their computers running instead of shutting them down and save energy.
