Mr. travelmad478 and I throw away almost nothing (luckily, both of us were this kind of person before we met/married!). Meat bones and eggshells are it, really. Very rarely, the produce we buy spoils before we can eat it--cheap Roma tomatoes, I'm looking at you!--but even then the spoiled stuff goes in the compost, which goes into the vegetable garden, so I'm counting that as utilized I freeze tons of things, including vegetable peelings/scraps for stock, chicken bones for stock, portioned-out tomato paste, ice cube trays of chopped cilantro, etc. I save and render chicken fat and bacon fat to use for cooking. We strictly save leftovers and do eat them...it pains me to throw anything away. We have in inventory, but rarely use, things like mayonnaise and ketchup, and they live in the fridge for literally years without spoiling--I am living proof that food preservatives work!

I'm only 55, but have the cooking habits of someone who came of age during the Great Depression, for some reason. This does not extend to all things (I like to get a new car every decade, for instance), but I do tend to keep items that still function for as long as possible, within reason.