Wine starts to deteriorate when oxygen hits it. Generally, a wine will last about a day if left opened in a kitchen, and up to three days in the refrigerator.
There are some inexpensive gadgets you can buy to preserve wine for longer periods of time. For instance, the Vacu -Vin system uses rubber stoppers and a pump-suction system to remove the oxygen from the bottle. The system will keep a bottle fresh for a couple of weeks and because of its new-found popularity, you can find it lots of places.
There are systems a little more expensive such as Private Preserve that involve inert gases and others that are geared more towards the professional or serious wine drinker, so ask your local wine merchant for advice about these.
Posted in: Wine