My wife and I normally split a bottle.
Sometimes we will open two and drink half of each. 1.5 bottles if one of them was really good, 0.5 if neither were very good.
Part of this is because, even with the fancy resealing contraptions, the wine never tastes as good (to me) if you keep it for more than 3 days.
I may be a young man, Brom, but that doesn't keep me from enjoying a 2 or 3 bottles a week. Why not every night? Well, we do not eat dinner together except for 2 or 3 times a week. :^)
Why keep track of how much wine you consume?
Why not keep track of which you like instead.
-Jeff (one of the many here)