One way I have come up with to combat stale snack foods and the inevitable toss, is to make the snacks into a "chex mix."
This batch in particular has old pretzels, cheezits, croutons, sesame seeds, and triscuits.
I added to it about 2 tbsp of butter; 1-2 tbsp of Worcester sauce (depending on taste), garlic powder, salt, pepper, onion powder, and seasoning salt. All to taste. Put it in the oven on 300-325 degrees (no higher) for 30 minutes or until crunchy. Take out and let cool about 10 minutes before eating. Now you have a new snack food that tastes different and uses up stale old food that you would have wasted anyway :)
Do you have any personal ways you save leftovers?
Another thing I do is to save my vegetable stumps, and anything that I would normally toss in a freezer bag in the fridge; when i fill up the bag, I boil all of the stuff in sort of a "garbage soup" for 1 hour. Drain all the "garbage" out and keep the broth; I pour mine into muffin tins and then put them in the freezer until they are frozen solid. Then remove and put in freezer bags, these now are 1 cup servings of vegetable broth. Yum!