Taste of old Pauillac...

[winecollector]

While you are right in that letting a wine sit for some time after opening is no substitute for proper ageing, it is a good way of finding out where a wine is at on the "time line" of its drinkable life. I wouldn't recommend it if you only have one bottle of something, but if you have several bottles or cases, it's about the best way to tell when a wine is likely to peak. I'll probably go five or six more years on the Lynch Bages before I open mine.

I've had wines that have taken a week or longer after opening, before they've become approachable enough to enjoy. These are wines that I'm guessing will continue to age for decades!