I wonder that no one has mentioned what my wine fanatic friends do. They blend very sweet wines with very dry wines of the same varietal, always have a decanter of that in their wine fridge because they know people who don't like either very dry or very sweet and are not very picky, as long as it tastes good to them.
They never "throw away" wine. Some that they consider "undrinkable" after a day or so, they save for me and I make vinegar from it.
And from time to time give them a bottle of my very good vinegar which I have been "cultivating" for 20+ years.