Two very different women are reading this.

One has an invitation on the fridge and three weeks to work out what she is wearing to her friend’s fiftieth.

The other is the friend. It is her party, she has not thought about what she will wear, and she is quietly dreading it more than she will admit.

Black dress worn with a green jewelled statement choker and a colourful cuff

Those two need completely different advice. So this is both, guest first, and the second half is for the woman whose night it is.

The invitation will not help you

Fiftieth invitations are written by people who are organising a party, not a dress code, and it shows.

Smart casual means no jeans and no suit. A dress you would wear to a nice lunch, or good trousers with a proper top. It is an instruction not to turn up in what you wore to mow the lawn, which is a bar worth clearing by a comfortable margin. The fuller version of that dress code is in the smart casual guide.

Cocktail means a dress or a very good jumpsuit, and it is rarer on a fiftieth than people fear.

Dress to impress, which appears surprisingly often, means the host wants effort. Give them effort.

Nothing at all on the invitation is the most common and the most solvable. Ask the host what they are wearing. One message, thirty seconds, and it removes the entire problem.

The one question that answers most of it

Where is it, and will there be chairs.

A backyard or a deck. Grass swallows a stiletto and decking gaps eat the tip of one. Block heel, wedge, or a very good flat.

A function room or a club. Air conditioning, a hard floor, and standing. Take a layer and wear shoes with some structure under them.

A restaurant or a long table. The only setting where a fitted dress is genuinely comfortable all night, because you will be sitting in it.

A winery or somewhere out of town. Two temperatures, a car park, and usually gravel. Dress for the transition rather than the arrival.

And a boat, which happens more often than you would think. Flat shoes, non-negotiable.

The rule that makes a 50th different from a wedding

This is the part that trips people up, because they bring wedding habits to a birthday.

There is no outshining anybody. Nobody turning fifty is worried that a guest will upstage them. Quite the opposite. A room full of people who made an effort is the actual gift.

Black is entirely fine. So is white, which at a wedding would be a problem and here is simply a colour.

Under-dressing is the only real mistake. It is far more visible than over-dressing and it reads as not having cared, which at a milestone is the one message you do not want to send.

So the brief is simply: a notch above what you would wear to dinner with the same people. That is the whole thing.

Dressing for a room with an eighty-year-old and a twenty-year-old in it

A fiftieth is the most age-mixed party most of us ever attend. Her parents are there. So are her children, and possibly her grandchildren.

Cobalt blue dress worn with a bright pink leather jacket and embellished platforms

Which is an argument for colour rather than for coverage. A strong colour reads well to everybody in that room. A very short hem or a very low neckline makes some of them uncomfortable, and being the outfit somebody’s mother mentions later is nobody’s ambition.

Choose a colour that suits your colouring rather than one that suits the theme, because you will be in photographs with four generations and the light will be whatever it is. There is a whole post on the colours that actually suit your skin tone if you have never worked yours out.

And dress for the person, not the decade. Fiftieths sometimes come with an eighties theme, and if yours does, commit properly or not at all. Half a costume is worse than none.

The formula, for the guest

A dress, or good trousers with a lovely top. Both work. Neither is more correct.

One substantial piece of jewellery, and this is where most outfits are won. A black dress with one real necklace is dressed. The same dress with three small delicate things is not.

Shoes you can stand in, which I will come back to because it matters more than anything else on this list.

A bag that hangs off you somewhere. Both hands are spoken for at a party like this, between a glass, a plate and being handed somebody’s phone to take the photograph.

And a layer that belongs to the outfit, not a cardigan grabbed from the car at ten o’clock.

Years ago I wore a Bardot little black dress that I found in an op shop in Paynesville for four dollars, with a choker I had made by tying a brooch of my mother’s onto a ribbon. It got more comment than anything expensive I have ever owned, and the whole thing is written up in that post about statement neck candy. Prices have moved since then. The formula has not.

If you do not want to wear a dress

A great many women do not, and occasion advice tends to forget them entirely.

Black leather pants worn with a long studded top and a lime peplum jacket

Tailored trousers with a good top is the most underrated party outfit there is, and it is more comfortable than any dress.

A jumpsuit, if you have one that fits properly, which is a big if. Try sitting down in it and work out the bathroom logistics before the night.

Leather or faux-leather trousers with a long top over them. I have worn this to more evening things than I can count. Layering a longer top over the top is what makes it wearable rather than daring.

And a good jacket over anything does the same job a dress does, which is to say it tells the room you got ready.

The present, which nobody plans for

Small thing, and it changes the first twenty minutes of your night.

You are arriving carrying something. A gift, a bottle, a platter, and often all three at once, which is why so many people do the first hug of the night with their elbows.

Put the card on the present at home. Writing it in the driveway is a tradition and it is also how people arrive flustered with ink on their hands.

And there is always a table for gifts, so plan to put things down within a minute of walking in and then to have nothing in your hands for the rest of the evening.

Shoes, because you will be standing

Four hours. Possibly five. On grass, or on a hard floor, holding a drink.

Bronze T-bar wedge sandals with a beaded medallion at the toe

A block heel or a wedge gives you the height without the balancing act, and on grass it is the difference between walking and sinking.

A flat is not a defeat. A good metallic or embellished flat at a party reads as somebody who has done this before.

Whatever you choose, wear them around the house first, on a hard floor, for longer than feels necessary.

And if you insist on the stilettos, put a pair of flats in the car. Everybody who has ever done this has been glad of it by eleven.

Now, if it is your fiftieth

Different job entirely, and a harder one.

Black dress with a gold embellished yoke, worn with sheer tights and ankle boots

You will be hugged about a hundred times. So nothing stiff, nothing that needs rearranging afterwards, and nothing strapless.

You will be photographed all night, by everybody, from every angle, and those photographs are the ones that come out for the next twenty years. This is the single strongest argument for wearing something you already know you look well in.

You will probably speak. Even if you have sworn you will not, somebody will hand you a microphone. Whatever you wear needs to work standing at the front of a room.

You will be warm. Attention is warming, the room will be full, and you will be moving the whole night.

Wear colour. Every instinct on a big birthday says wear black because it is safe. Black is safe and it is also the colour you will be least pleased to see in every photograph from your own party.

And do not buy a new personality for the night. A fiftieth is not the moment to debut a silhouette you have never worn. Wear the best version of what you already are, which is what everybody came to celebrate.

The trap of the milestone

There is a particular pull at fifty, and it goes in two directions at once.

One pull is to dress younger, to prove something. It never works, and it is the one thing that genuinely does add years.

The other is to dress sensibly, to settle, to choose the safe navy thing. That adds more.

The way through is neither. It is clothes that fit properly, in fabrics that are good, in colours that suit you, with one strong accessory. That formula has never looked like anything other than a woman who knows what she is doing. I wrote the long version of this argument in how to dress in your forties without looking older and every word of it applies with more force at fifty.

Back in 2014 I wore a sleeveless dress with a gold bodice in the same week Dannii Minogue wore gold on the X Factor, and I was quietly pleased with myself about it. The useful part of that gold rush post is not the dress though. It is the advice in the middle: pick somebody whose style you admire and take pieces of it, never the whole look.

Doing it without spending

Look properly at what you own first. Not a glance at the wardrobe, an actual hour with the shoes and the jewellery out. Most women own two or three things that would be right for a fiftieth and have stopped seeing them.

Then change one element. New earrings, a different bag, a jacket over the dress you have worn twice. That is usually the entire distance between what you own and what you need.

Then op shops, where occasion wear is the best value in the building because nearly all of it was worn once and hung up forever. Melbourne’s op shops, suburb by suburb, if you want to know where to start.

And borrow, cheerfully. Party clothes are the category where everybody has something hanging up that has had one outing.

The short version

  1. If the invitation says nothing, ask the host what they are wearing.
  2. Smart casual means no jeans and no suit. Dress to impress means effort.
  3. Ask where it is and whether there are chairs. That answers most of it.
  4. Black is fine, white is fine, and under-dressing is the only real mistake.
  5. Colour reads well to a room that spans sixty years.
  6. A dress or trousers, one substantial piece of jewellery, a bag with a strap.
  7. Shoes you can stand in for four hours, and flats in the car if not.
  8. If it is yours: colour, comfort, and something you already know you look well in.

If you are the guest, this is one evening of work and you can do it yourself tonight. If it is your own fiftieth, it deserves better than half past nine on the night, pulling things off hangers and liking none of them. Hand that to somebody else: a two-hour session with a personal stylist in Melbourne runs to $299, and more often than not the dress has been in the house for a year already. Where the hunt really is on, there is the $399 Half Day for that, out with a Melbourne personal shopper, and it settles the thing properly. Either way, not in the fortnight before.

Now go and find out whether there is grass.

And now you’re Looking Good Girls.

“Even to your old age and grey hairs I am he, I am he who will sustain you.” Isaiah 46:4.