I am a firm believer that if it is not smelly, that it is still good. One thing to consider is that when food begins to go "bad" it doesn't get "bad" right away. Remember, the date on many foods doesn't read "expiration date" or "use by," but rather says thing like "sell by" and "best if used by." Many foods, including meats, will first begin to change flavor, and only after that will they begin to go bad. The difference between a fresh hamburger, and one that was made from meat past it's prime, is texture (fixable with bread crumbs and milk), flavor (fixable with seasonings), and of course that you must have it well done.
Eggs last well past their expiration date. I once had eggs last a month past their date. Of course, if you get them from a farmers market they will go bad before the expiration date. My grandma taught me that you can tell if an egg is no good by spinning it. If it slows right away it's still good. If it spins freely then it's either a boiled egg, or a rotten one.

Pork gets slimy and rancid very quickly, so I usually throw that out. Tough to salvage taste when its so nasty.

As stated previously, lots has to do with how things are handled.