I must admit, I tend to finish what I start and a bottle of wine is no exception. But on the days when I can't finish a bottle, or use just a little for cooking, I certainly don't want to just throw out the rest.
Exposure to oxygen ages wine and the more oxygen it is exposed to, the quicker it ages. During the aging process, the flavors will open and change, and you can have a completely different wine 48 hours after you open it, just from oxygen exposure.
More years ago than I care to admit to, I worked at a restaurant that served wine by the glass. Great for patrons, not so great for the...