How long does a screw-top bottle of Port last after it's been opened?

what kind of Port is it?

Screw top?

Until it’s gone.

It’s probably not as tasty as it was, but it’ll be drinkable for six months or so. After about a year, meh, best used just for cooking.

It is a fortified wine. It will last decanted for weeks or even months as long as it has some sort of top on it.

@Blondesjon – good one!!!

Not long at my house.

My husband keeps his in the refrigerator for several months and it is just as good as when he first opened it.

No need to keep it in the refrigerator, you can keep it at room temperature for months.

Bottom line:
You can always use it to cook with, if and when it becomes un-drinkable…