how do you know when things are off?

expiration dates are more of a guide than a countdown to certain doom but things like honey have an indefinite shelf-life. We know that when milk gets chunky it's probably time to throw it or sell it as yoghurt. If you don't trust your nose to see if something is ok or not, then the guys at realsimple.com have a list of items in your home and how long they last... even shampoo(???).
Surprising Expiration Dates: "e"