As you can see, the software cleans things like browser cache, Windows Explorer cache, and system cache which we are usually too lazy to clean by ourselves one by one. But of course, there's no reason to waste your computer's performance by not cleaning them since this can't get simpler.
CCleaner also supports cleaning cache of the applications you have such as Skype and such, which makes it a quite good bundle overall. You won't ever have to clean any cache manually anymore after you start using CCleaner.
It also has the option to analyze and tell you what you should clean by giving statistics about the software you are using in the right pane. You can see which cache is taking how much space by looking at the right pane and clean the ones you want, and leave the others.
CCleaner also offers registry cleaning, which is kind of a sweet feature. Registry entries tend to get messed up and stay there for long time even if they aren't used anymore, so it can't hurt to scan for registry issues every now and then and clean it.
Lastly, there are some extra tools in the software such as a built-in uninstaller, a startup manager similar to msconfig, a system restore utility, and a drive wiper. The drive wiper is also quite useful, since it deletes the files that are deleted before, (similar to Revo Uninstaller, which I covered in one of my posts) opening up more space and making them unrecoverable. The drive wiper also gives you the option of deleting the whole drive, also known as formatting.
My recommendation would be to run CCleaner's Cleaner & Registry tools once per day right before you close your computer, so you can start fresh the next day. That's what I personally do and I can say I'm satisfied with the results.
I hope you enjoyed the read!