How do people preserve wines, champagne? How do people preserve wines and champagnes for decades? Is there a special method or is it like keep in wine storage or cupboard and forget for some decades to be better in taste?
This really depends on the drink itself. Some wines are meant to keep for years. Others should be drunk immediately. Most should be drunk within 1 or 2 years. So choose your wine carefully. There are various vintage wine guides online.

That said, once you have chosen a wine meant for ageing, you do want a cellar (or if that is not available, a refrigerator designed for the purpose) that will be able to give you consistent:


Temperature: around 12-13 C (55 F)
Humidity: around 70 percent
Light: keep wines out of sunlight or even bright lights


And if the bottles have cork stoppers, they need to be stored on their side to prevent the cork drying out. This isn't an issue with screw tops.

And that's pretty much it. If you don't have a cooler or cellar, keeping them in a cool, dark cupboard is still going to help...