By the first week of December the calendar has usually filled itself in. A charity benefit, two dinners, the office party, something at a gallery, drinks with people you only see at this time of year, and New Year's Eve sitting at the end of it like a deadline. Six invitations, six photographs, and a quiet pressure not to appear in the same thing twice.

The usual response is to buy six outfits. The better one is to buy one or two that are genuinely good and learn to move them around.

Start With the Midi

The season belongs to the midi. It carries enough fabric to feel like an occasion, it works with a heel or a boot, and it photographs well in low light, which matters more in December than at any other point in the year. A floor-length gown commits you to one kind of evening. A mini commits you to another. A well-cut midi dress will take you to almost all of them.

Look for shape rather than embellishment. A defined waist, a skirt with some movement in it, a neckline that frames rather than competes. Those are the things that make a dress look considered in a room full of people who have also made an effort.

Texture Over Sparkle

Sequins have their place, usually on 31 December. For everything before that, texture does more work and dates less quickly. Ribbed knit bodices, mixed media dresses that pair a fitted top half with a flowing skirt, brushed fabrics and anything with a subtle sheen all read as dressed without announcing it.

A mixed media dress is quietly the most useful thing you can own this month. The knit half keeps it comfortable across a four-hour event. The woven half keeps it from looking like something you would wear to lunch.

Build a Palette and Stay In It

Three tones, chosen once, will do more for you than a wardrobe of individual outfits. Chocolate, cream and gold. Black, charcoal and silver. Burgundy, rust and bronze. When everything sits in the same family, accessories become interchangeable and a dress you wore a fortnight ago stops being recognizable as the same look.

Deep color also suits the season's lighting. Candlelight and string lights flatter olive, oxblood and forest green in a way that does not happen in July.

Change the Frame, Not the Dress

This is where one dress becomes six. The outfit people remember is rarely the dress on its own, it is the whole frame around it.

Swap the shoe. A block heel for dinner, a knee-high boot for a daytime event, a metallic sandal when the invitation says black tie optional.

Swap the layer. A tailored blazer over the shoulders turns a soft dress sharp. A long cardigan takes the same dress somewhere relaxed. A cropped jacket changes the proportion entirely.

Swap the jewelry. One substantial earring does more than four small pieces, and it is the thing that reads first in a photograph.

Belt it, or do not. A dress with a smocked or elasticated waist looks different again with a thin belt over it.

Four changes, each of them small, and nobody is counting.

Think About the Whole Evening

The dresses that fail are the ones that only work standing up. Before committing, check you can sit comfortably through a long dinner, that the neckline stays where you left it, and that you can get to the car without managing the hem.

Pockets are not a frivolous thing to want in December. A phone, a lipstick and a key, and the clutch stays on the table where it belongs.

For the Travel Weeks

Plenty of the season happens somewhere colder. The same midi will travel north perfectly well with a fine long-sleeved layer underneath, opaque tights and a proper coat over the top. A dress that only works in one climate is a dress you will wear twice.

The Point of Buying Well

Six outfits bought in a hurry tend to produce one you actually liked. Two bought properly will be in the rotation next December, and the one after that. Choose for cut and fabric rather than for the party you are thinking about this week, and the season becomes considerably less work.