Does older wine, mean better wine?
Not necessarily. There are several factors that go into aging wine. First and foremost, most wines are made to be enjoyed right away. Translated, this means that most wines are not supposed to be laid down in a cellar to mature - they will get old and spoil.
Think of wine like any other old thing or antique. Generally, as things get older, they become junk. However, there are some treasures that get better (or more sought after) over time. Just like most old bicycles, records, cameras, cars, antique furniture, and paintings get worse with time - the same is true with wine. But, just like some bicycles become collector's items, some records become treasures, and on and on, the same is true with wine - so think twice before thinking you can put that bottle in your cellar and it'll become a treasure over time. Furthermore, like with fine art and antique furniture, it is important that wines are aged in the proper environment.
Important factors in the aging of wine include temperature, exposure to light, and humidity. All wines have a window when they are at their peak. Therefore, if you jump the gun or if you wait too long, your wine may not be putting its best foot forward. To find out when you should consume your wine, it is often-times best to ask the winemaker. Simply call or email the winery, and they should be able to tell you when the best time to open your bottle will be. If you cannot get in touch with the winery, this information may also be available via online sources.
Here is a quick rundown on how to age wine: Sunlight - keep aging wines away from sunlight. Temperature - the optimal temperature to age wines is somewhere between 55 - 65 degrees Fahrenheit. Humidity - as close to 70% as possible. Bottles should be laying down on their side and should be spun in regular increments in order to keep the cork moist. Beyond these factors, aging wine takes (here comes the big secret) time! In order to age your wines correctly, you must be very patient. A good strategy for building your cellar is to order wines and set aside some for aging and some for drinking. This way, you won't feel like you're completely sacrificing the "now" for palate-nirvana later. As time passes and you continue to add to your cellar, you won't feel so guilty about popping the cork on one of your older bottles.
Remember that most wine is for drinking; not collecting. So enjoy your wine when it's at its best, and then try another bottle. If you want to learn more about aging wine, check out this post from Wired.