Yup, one word: Foodsaver.
When our kids left, we changed nothing in what we cook or how much we make. We just vacuum pack all the leftovers. We've had our Foodsaver for almost a quarter century and in that time I don't think I've ever thrown anything out. We've often had leftovers from the freezer that are almost two years old. We buy ham at Costco and it sometimes takes three months to finish that, and even though it is stored in the fridge and not the freezer, it is in perfect shape (we just had ham in our scrambled eggs for Sunday breakfast, and we bought the ham in December).
We bought ours when it was a very new contraption and before it ever appeared in those TV infomercials. However, when those commercials first started back in the late 1990s, we watched part of one and they had this really good tag line that actually is quite true:
"They're not leftovers; they're second helpings!"