It all depends on wine type, PH level, alcohol by volume level, and type of cork used. Storage conditions play a big role too.
If the wine is highly acidic, or tannic, it can last YEARS, and sometimes even decades. Wines with higher alcohol (13.5% ABV and higher)will last much longer too.
Corks play a large role: 1.5" agglomerated corks are rated for about 1 year. 1.5" full corks are rated for 3 years. 1.75" can range from 2 years to 10 years depending on quality. George's FVW corks are reference grade, and I think are good for up to 7 years. At least from what I can tell from the pictures. Synthetic corks are rated for up to 5 years and beyond.
If your wines suffer from temperature fluxuations (Winter, spring, summer, fall) it will dramatically reduce the aging ability. Wines that are in constant temperatures throughout the year (1-2 degrees), will last much much longer.
k-meta assists the wine's ability to ward of oxidation, as oxygen will enter the wines eventually through the cork. When temps fluxuate, the wine will expand and contract, which causes the cork to breath more. The better the quality of the cork, the less oxygen penetrates. So you can see that it is all related. I've had some kit wines go over 8 years in my parents cold room, and those were just fine! Others have gone bad in 2 years.