Every night, when I'm done with my computer, I shut it down completely. The next day, when I start it up, it takes a good long while. And sometimes, when I shut it down at night, it takes forever to shut down because Windows wants to apply updates right then. I've heard about sleep and hibernate, but they confuse me, so I don't use them. Should I use one of those features rather than shutting down completely? Certainly shutting down your computer when you're done with it for the day does save a little bit of power over your computer's using no power while it shut down.
On the other hand starting it backup can take some time. We tend to use either sleep or sometimes called suspend mode or hibernate to save time when shutting down and starting back up. The differences are pretty substantial. Hibernate takes an image of the memory of your computer and saves it to a file on your hard drive then when the computer starts back up, it takes that information and loads it right back up into memory. So you start up exactly where you left off. Using hibernate mode takes up as much space on your hard drive as you have memory in your computer.
So if your computer has for example eight gigabytes of memory. You'll find that hibernate mode takes up eight gigabytes of space on your hard drive which you may not have to spare. In addition using hibernate mode your computer is completely turned off. It just loads that file from the hard drive when it starts up the next time so really don't save a whole lot of time at startup.
Sleep mode on the other hand does save you time. It leaves the computer in a low power mode and preserves the state of your applications you are running. If you put your computer to sleep and then wake it from sleep, this can happen very quickly. It does take a tiny bit of power but I think it's worth it because you don't need to take the time to restart your computer the next day. Take a look at sleep and suspend mode on both Mac and Windows computers. It may save you some time and effort.