IMHO don't mess with stuff unless you are really needing the last gig of room.
that aside windows does serveral things with drive space that are there to keep folks from losing files and to allow you to rollback system chnages.
if you turn things off you may later not be able to recover from some common problems.
for example when you install new driver updates, windows shadows a copy of the prior version so you can go back if the new ones are broken for some reason.
also windows allocates recycle bin storage space as a percentage of the size of the drive.
some other apps will hold amounts of temp files and things like ie browser history, cookies etc...
also there may be windows cleanup tasks you have setup that once a week or month will clear out the oldest stuff
that can free up space for you like you describe.