How long will my wine last?
This is one of the most important questions new winemakers ask, and there are a few different answers, depending on what they're really asking.
First answer is, it depends: If you store it in a good location (dark, quiet, on the cool side with a steady temperature) it will last as long as any commercial wine you buy for under $100.00 and will improve in much the same way. Both wines are made from the same things (delicious grapes) and both will respond well to gentle treatment.
Second (and perhaps more accurate answer) is it will last a far shorter time than you're planning. Not because the wine won't store or age well, but because as soon as you make your own wine and have thirty (or sixty, or 120 bottles) on hand you're going to experience.
Vandergrift's First Law of Home Winemaking: "Wine consumption rises to meet all available sources of wine."
When you've got a healthy cellar it's nothing to open a bottle for a weeknight dinner, or to open a second bottle on the weekend, or to serve a bottle when guests drop in, or to take a couple of bottles to a party or barbecue . . . and suddenly, you're out of wine.
Vandergrift's Second Law of Home Winemaking: "You don't actually know how many friends you have until people find out you make your own wine."
The good news is, you can always make more . . . and wind up with even more friends!
As for cellaring wine to follow its development, that's where cellar planning comes in: from every batch try to save at least six bottles to put away. Best if it's a full case, but that first law says you need to be realistic. Try one every six months or so to see how it evolves and changes. You'll see that every wine improves drastically over the course of two to three years, or even longer, and then holds just that long.
This is in accordance with Coate's Law (no relation to Vandergrift). A famous Master of Wine who started in the 1970's, he said that a wine stays at its peak drinking age for as long as it took said wine to reach this level of maturity. For example, a wine which takes three years to reach its peak will remain at this peak for three more years. The upshot of all this? You need to make more wine.