How long do red and white wine last once opened?

If you just want a glass with dinner and for cooking, you might want to consider boxed wine. I know that boxed wine has a reputation for being a bit trashy, but it will stay good in the fridge for up to a month. It's shelf life is only a few years, though, unlike bottled wine.

I asked my friend (who is a sommelier) and he said at the very maximum 3 days (refridgerated for white, room temp but cork in for red)

RED--1 to 3 days (2 days being average), depending on the wine. WHITE--It really depends on the wine. Some can last quite a while in the refridgerator, sometimes a week or two. Others will go bad more quickly. Wines with a higher sulfite content will be on the higher end of the range because sulfites prevent oxidation, whereas unsulfited reds (esp. organic wines) can go bad in a matter of hours. Acidity can also play into this; acidic wines (pH 4.3 or less, Italian reds are often very acidic) tend to last a little longer.

I left some wine for a few weeks and it tasted a lttle bit like vinegar but it still got me pi##ed

I usually recork, drink within 24hrs. Goes stale.

White in a fridge probably two days. Red wine I would say out of the fridge about four days. Obviously keep it airtight and away from heat and direct sunlight.

about 3.5 minutes at our house!!

I day for most white two for most reds if you remove the oxygen contact ( noble gas spray, vacu vin, smaller decanter with stopper) then you can extend the time

20 MINUTES