Eye colour. Skin tone. Straw or felt? Shrinkage.
There's a lot to think about when selecting a hat that'll have you cutting a sartorial swathe through Melbourne's spring racing carnival.
Back in the day – say Humphrey Bogart's Day – any man worth his salt wouldn't have been seen dead in public without a dapper hat.
But if you're a modern man, unused to putting a lid on it, where do you start?
Fitted to perfection
"The secret really is having it properly fitted. What a lot of people do is choose a hat that's either too big or too small," says hatmaker Oska Truffaux.
Too tight, and it will sit awkwardly high on your noggin. Then again, too big should also be avoided. "It kind of flops over their ears and you can look a little foolish. It's sort of like wearing shoes that are too small or too big," says Truffaux.
He specialises in Panama hats –the quality kind, made of Panama straw.
"Most of the hats in the world are made out of plastic. They tend to be very poorly made and it looks really obvious," he says. "If you wear a $50 suit to the races, everyone can tell, and if you wear a $20 hat, everyone can tell you're wearing a $20 hat."
The cheap ones won't shrink, but Truffaux says buyers of quality hats need to buy it a little bigger than they need. "The thing with the Panama, there's a shrinkage factor."
The trick is to have your hat fitted with a spacer initially, which will make the hat sit nicely on your head, and leave room for the inevitable shrinkage.
Milliner and hat lover Phillip Rhodes agrees that quality is key. "You probably need to go to a reputable hat maker if you want to cut a bit of dash," he says.
"Buy a hat that fits your head. Nobody wants a headache, and hat hair is one thing but is not quite as bad as a red mark across your forehead," says Rhodes.
"If you actually get hot in your hat, you probably need to realise that if you take your hat off while it's hot, it will cool down off your head and likely shrink."
The same goes if you take your hat off when it's damp. Which brings us to what Rhodes describes as "the agony of etiquette".
The days of doffing your hat are long gone, but what about race etiquette?
Rhodes says the public areas of the racecourse, including the marquees if you're standing up, are fair game for hat wearing. However he'd consider it bad form for a gent not to remove their hat if sitting down for a restaurant meal.
Stay ahead of the game
So what kind of hat should you go for?
"Men can happily wear a fine felt hat in the spring still," says Rhodes. "You can wear a straw hat, but they can be fairly limited in their selection generally."
However if you do decide to go for a straw hat, such as a Panama hat, he suggests opting for a natural colour, rather than a dyed job.
In that case, you'll need to keep in mind matters such as skin tone, eye and hair colour, and the dimensions of your face.
"I would suggest if you have a broad face you should probably avoid the current trend of wearing a narrow-brimmed hat. You probably should be a bit honest with yourself," warns Rhodes.
Mix and match
He suggests avoiding the pork pie hat, and going for something more like a Bogart, which is much more flattering.
As for matching it with your suit, Rhodes says that's not important. Disparate colours will likely look better.
"The majority of men will probably take quite a conservative approach therefore the grey felt hat would probably go with most suits they'd choose," he says.
But even then, there is plenty of headroom so to speak.
American milliner Nick Fouquet's hats are an intersection of history and tradition, the end result being a piece of wearable art. His "kashmir" design, for example, ticks the all the boxes of a traditional hat but with the added character of leather and brass detailing and signature match motif.
The creative – who counts clients such as Pharrell Williams and Madonna – will be in the Birdcage at this year's carnival and hosts a pop-up the weekend before the Cup. "Choose a classic style that's got a playful twist," says Fouquet. "Look for something that is classic in shape but also a little fun and eccentric."
A hat for every head
Oska Truffaux says you should either buy a hat to suit your style, or to suit your face.
For instance, a caramel-coloured hat will flatter a man with brown hair and freckles, while "a white hat will make you look terrible, it will make you look super pasty".
"If you're a redhead for example, a dark green looks great."
Truffaux says the idea of a hat is that it frames your face. "It creates a halo around your eyes, and makes you look intriguing."
He agrees that it's better if the colour is a little different than your suit. However matching the trim or band of the hat to your suit is to be advised.
If you're wearing a dark blue pin-striped suit, for example, Truffaux says a white hat with a dark blue band can look striking.
Pull your head out
What about ditching the hat altogether?
"You're being invited to step up and wear a hat, so yeah, it's worthwhile doing," says Truffaux. "It's the one good excuse you've got to wear a nice hat."