When I first started drinking wine I found that I didn't like wine, especially white wine, the next day. I soon learned that once you pop that cork your on borrowed time. The chemical processes called oxidation starts to break the wine down and can eventually turn it into vinegar!
With my Vacu Vin I've been able to go back to bottle the next day and it be just as good. It claims to save wine for up to two weeks. I don't know about your house but I've never had a bottle of wine last in my fridge for two weeks! But I can safely say at it does hold it for a few days to a week.
This is a great video from the WineEnthusiast on how this product works.