Regarding aging wines, it depends on the individual wine, whether it is ageworthy or not.
Some wines and certainly any champagne should be drunk shortly after purchase, since they do not get any better. Other wines do benefit from aging, but it is wrong to say that any wine will get
better and better. Every wine goes bad at some point, some sooner, some later. Generally red wines age better than whites. Within the whites, sweet wines (i.e. dessertwines) age much better than dry wines and high acidity (like in German
Riesling, dry or sweet) also benefits the agability of the wine.
With red wines, high tanin and intense wines (Cabernet Sauvignon) age better and longer than fruit driven wines (Pinot Noir).
Again, it depends on the individual wine and your wine merchant should be able to answer the question how long you can (but you do not have to) age a wine. Storage conditions is an important factor regarding the ability of an ageworthy wine to age gracefully.