Unless a glass of wine is chugged, one can actually feel a difference from the first sip to the last as the wine in the glass is oxygenated. That's where I learned to take decanting seriously...

(Semi-)Pro tip: instead of putting the wine in the refrigerator to be chilled (if that's your play) put the empty decanter in to be chilled and then pour the room temp wine into it. You get some chill to the wine, but (IMHO) not too much...