Do I need MS Office on my computer if I never use it? Does it do things in the background that I need it for?

It might be interlinked with other M$ programs, so I would leave it alone.   I have deleted or uninstalled M$ stuff and that caused a big problem in the P.C.   Not going to repeat that mistake twice.

If you did ever need it, AbiWord is a free alternative.

Easiest question of the day: If you don't use or need it, uninstall it. Give your hard drive a little room

your PC would run just fine without it if thats what youre asking. And yes it does work in the background. Almost all microsoft software have some sort of background process that monitors for updates and changes, much like google apps. Most of the time though this process can be disabled inside the app's settings

No need if you don't use.

Don't buy or install if you don't need it. Good for you.

No, if you don't need it, uninstalling will do nothing to upset your system. Your operating system is not reliant on it at all. It's a product that lets you open various types of office documents, nothing else.

No. you do not need it.   If you want to type a letter you have Wordpad, which comes with Windows.

You don't NEED it, but it would be nice to have.  In such a case, where you receive a file in doc, docx, etc file format, you can always download OpenOffice from Open Office.org which is free. 

If you have no use for it, it makes no sense to install it or keep it installed. It does things in the background like updates for the programs, but if you don't use them it won't help you.