The biggest one I know is to put a chamois in your bathroom. When you get out of the shower/tub and the mirrors are all steamy, use the chamois to remove the steam. Clean mirrors and no cleaner! (I'm not sure this would work with many people sharing a bath, but it works fine with DH and myself.

Also, rubbing alcohol works great to shine chrome.

Anyway, I don't keep any glass cleaner in my bath any more because I do these.

jd