Is a waistcoat worth it?

A waistcoat — the vest — turns a two-piece suit into a three-piece. It costs a hundred and fifty dollars with us, and the question is whether that buys you anything you will use.

What it actually gives you

Flexibility. Jacket on, it is a formal three-piece. Jacket off, you are still properly dressed rather than a man in a shirt — the waistcoat keeps the line of the torso and covers the shirt's midsection. For a long day that runs from a ceremony to a dinner, that is genuinely useful.

A cleaner line. A waistcoat holds your shirt flat and hides the transition at the waistband, so the whole silhouette reads as one piece. It is why three-pieces photograph so well.

Warmth. A third layer of wool across the torso, which matters more than you would guess in a cold building.

Where it earns its keep

Weddings, first and foremost — your own, or standing up in someone else's. Formal daytime events. Any occasion with photographs, because the extra layer reads well in a picture in a way it doesn't always in a mirror.

It is less useful for ordinary office wear, where it can look like you are trying slightly too hard, though that varies a lot by industry and city.

If the suit is for a wedding, get the waistcoat. If it is your first work suit, skip it and put the money toward a second pair of trousers.

The one rule

Leave the bottom button of a single-breasted waistcoat undone. The story is that Edward VII left his open because he had grown too stout to fasten it and the court copied him; whether or not that is true, waistcoats have been cut on the assumption ever since, and a fastened bottom button pulls the fabric awkwardly across the hips.

Length matters

A waistcoat must be long enough to cover the waistband of your trousers completely, standing and sitting. A glimpse of shirt between waistcoat and trousers is the one way a three-piece looks wrong, and it is a measurement problem, not a wearing one — which is a good argument for one cut to you rather than bought off a rail.