I do, often, unfortunately. It gets poured down the drain.
They do make cans of wine... I know it's a crazy idea, but my friend who likes wine loves the single serving size.
Pretty sure that isn't the only brand I have seen.
A bottle is obviously better long term.
For a joke, my family got me a 750ml glass a couple of Christmases ago. I have yet to use it.
I can drink a bottle myself lunch to bed on a weekend, but not every weekend.