Using decanters regularly is a sign of eccentricity, like wearing a bow tie.
I have a moderately large collection of decanters but tend to use them on ceremonial occasions only. Decanters have great decorative value. I particularly like magnum decanters and own several, despite having little opportunity to use them.
Apart from adding a little gravitas to the dinner table decanters are a good way to remove sediment from aged wine and are a good way to aerate wine, although the benefits of aeration are disputed by some wine scientists. Exposing red wine to air does seem to soften the tannins a little although, to quote no less of an authority than Professor Émile Peynaud, only wine with sediment should be decanted and then served as quickly as possible. Peynaud believes that wine loses its aroma when exposed to air and if it needs aeration to remove or reduce a fault, such as reduction or mercaptans, a quick swirl of the glass will do the trick.
Peynaud may not have had much experience with wine from bottles sealed with screwcaps. In my experience, red wines (and some white wines) from bottles sealed with screwcaps do respond well to a little air time in a decanter.
The appropriately named Decanter magazine conducted a blind panel tasting where wines sealed with both corks and screwcaps were decanted for an hour and compared with freshly poured samples. They concluded that decanting had little benefit for red or white wine sealed with either screwcap or cork.
I recently set up my own simple comparative tasting for a group of students. A bottle of red wine was decanted for an hour while a second bottle was opened and poured. Everyone thought the wines tasted different with a majority preferring the “softer and mellower” decanted sample. Those who favoured the freshly poured sample liked it for its “freshness and punchier flavours”.
I concluded that if you are a “taste person” then don’t decant, but if you are a “texture person” then you might consider routinely sloshing your red wine into a jug or decanter.
The downside of using a decanter is that they are fiddly, harder to pour than a bottle, difficult to clean and a pain to wash. If you like your wine aerated there are many very effective aeration devices that will do it a glass at a time.
(The image is of a Riedel Black Tie decanter that I own but have never used because it seems to fragile and hard to wash. It does look terrific though.)