For more than a century, men's formal attire has revolved around one item of dress: the suit.

Get it right, and you'll have something in your wardrobe that will come in handy time and again, whatever the occasion.

Whether a new job means you're now wearing suits to work, or an event requires formal attire, you want to be getting a return on your investment.

That means a suit that looks good for years to come. Here's how to make that happen.

What to know about wool

Wool is breathable in summer, insulating in winter and holds its shape. It is the perfect material for suiting.

Patrick Johnson is a made-to-measure suiting specialist who works in Sydney, Melbourne, London and New York.

"Wool is just a really versatile fabric," he says. "It's breathable, warm, it's great for travelling, and it doesn't crease too much."

Of course, there's wool and there's wool. When shopping for a suit, there are questions to ask about the fabric:

"What's the weight?" Wool has a "gram weight", which refers to the weight of a metre of the fabric. A good weight for an Australian suit is 250–300 grams, says Mr Johnson. Much heavier and you'll have a suit that's too warm. Go too much lighter and you'll be compromising on the longevity of your suit.

Wool has a "gram weight", which refers to the weight of a metre of the fabric. A good weight for an Australian suit is 250–300 grams, says Mr Johnson. Much heavier and you'll have a suit that's too warm. Go too much lighter and you'll be compromising on the longevity of your suit. "What's the supercount? " The supercount is a measure of the wool's fineness. If the wool has a supercount of 100 — referred to as "super 100s" — it means one kilogram could be weaved for 100 kilometres in a single thread. For a mixture of quality and durability, look for something in the super 100s to super 130s area.

" The supercount is a measure of the wool's fineness. If the wool has a supercount of 100 — referred to as "super 100s" — it means one kilogram could be weaved for 100 kilometres in a single thread. For a mixture of quality and durability, look for something in the super 100s to super 130s area. "Where was the wool woven?" Patrick Johnson says the best quality wool in the world comes from merino sheep here in Australia. As for the world's best wool mills, they're in Italy (to be specific, the Biella region).

Cheaper jackets are often made with wool blended with a synthetic fibre, such as polyester or nylon. Synthetics don't breathe like wool. They can have a shiny, plasticky look and are to be avoided if possible.

Full canvas, half canvas, fused?

Traditionally, suit jackets are made with a layer of canvas and horsehair between the outer woollen layer and the lining.

The canvas helps the jacket keep its shape and drape naturally over the body.

Because canvassing is expensive and labour-intensive, mass market suits are often made with a "fused" lining, where the wool is glued to the lining fabric. A fused suit will be cheaper than a canvassed one, but are less durable because the layers can separate with washing and wear.

A good compromise is a half canvas jacket, which is canvassed in the chest, but fused further down.

You can tell if a jacket has been fused by pinching the fabric and pulling it apart with your fingers. If it's canvassed, you should feel three layers — the outer layer, the canvas, and the lining; fused suits will not have the middle layer.

You can tell it's a half canvas suit if you feel an extra layer in the chest piece (above the top button), but not when you pinch the jacket's front tail.

"For value for money, and for our climate, the half canvas suit is a really good option. It still gives you that form throughout the chest but with a lighter weight," says Tim Cecil, a Melbourne-based menswear retailer and great-great-grandson of Henry Buck, with a long family history in the trade.

Why navy is number one

As with fabric, the variety of colours available are endless. Unless you already own several suits, it's best to keep it simple.

Your first two suits should be in solid colours. Navy is versatile and looks good on just about everyone, so it's nearly always the best bet — especially if you're buying your first suit.

A classic, two-button navy suit is both classic and versatile. ( Unsplash, CC0 )

"You could make up your entire wardrobe with navy suits — and a lot of my clients do," says Mr Johnson.

"Even for funerals, a dark navy is fine — you don't need to wear black."

If navy is not your bag, a mid-grey or charcoal suit is another great option.

Mr Cecil suggests looking for something with a bit of texture in the fabric.

"You want something that jumps out a little bit without being too flashy," he says. "Some plain-coloured suits without texture can look a bit flat."

Breasts and buttons

If you're just starting your journey with suiting, begin with a single-breasted jacket. These have a single row of buttons, with a small overlap at the torso.

It's a classic look, and more versatile than the double-breasted jacket, which has a much larger overlap, and can look too dressy for more relaxed occasions.

There are plenty of options when it comes to buttons. If you're starting out, stick to a two-button jacket, the most versatile option.

Patrick Johnson's ideal first suit Colour: Navy

Colour: Navy Style: Single-breasted with two buttons, plus an extra pair of trousers

Style: Single-breasted with two buttons, plus an extra pair of trousers Material: Australian wool

Material: Australian wool Why? "Navy blue works on nearly everybody's skin tone. You can wear the jacket and trousers separately."

Three-button jackets come in and out of style, and are harder to dress down, but remain a great formal look, particularly for taller men.

"If you're buying one suit, I would just make it a two-button. It makes life easy," Mr Cecil says.

Fit

"You should always be comfortable. Nothing looks worse on someone than something that's too tight and uncomfortable."

That's Patrick Johnson's golden rule, and the same goes for suits that are too large, baggy, or long.

Finding the right shape or "cut" depends on your body shape. Here’s Mr Johnson’s tips to help find something that works for you:

To test if a jacket is the right length, hang your arms straight with your hands in a fist; the jacket should come to the bottom of your fists.

To test if a jacket is the right length, hang your arms straight with your hands in a fist; the jacket should come to the bottom of your fists. The shoulder is all-important: your jacket's shoulder should be hitting the bones of your shoulder — if it goes over your shoulder, it's too wide.

The shoulder is all-important: your jacket's shoulder should be hitting the bones of your shoulder — if it goes over your shoulder, it's too wide. If you're shorter and want something patterned, think about stipes rather than checks. Stripes can make you look taller.

Accessories make the man. ( Unsplash: Alvin Mahmudov, CC0 )

The details

A well-fitting navy or grey suit in a classic cut can easily be dressed up or down depending on the occasion.

When you want to make a statement, do it with your accessories rather than the suit itself.

"A tailored outfit should present a really clean, polished exterior, but there are infinite details you can bring that are really subtle," says Sam Fisher, a Melbourne-based designer of practical, fashionable and sustainable garments for men and women.

"If you want to bring your personality out, do that with your tie, pocket square or cufflinks.

"As trends change, you can change your pocket square, but changing your suit is more difficult."

When it comes to ties, once again, plain colours are the best starting point, says Mr Cecil.

"Subtlety is really nice. You can play with the texture and the fabric of the tie. Something in grenadine silk has more of a knitted look, which can make the tie something more than just a solid bit of colour."

Try to mix up the colour and patterns, Mr Cecil adds. It's nice to have a bit of contrast between your shirt and the tie, as well as your tie and pocket square.

Look after your investment

When you're not wearing your suit, don't let it sit folded in a wardrobe or crumpled on the floor. Hang it up.

If you get anything on the fabric, you're best off trying to spot clean the affected area and then let it dry, says Mr Cecil.

The harsh chemicals involved in dry cleaning can affect the wool, so avoid the dry cleaner if you can. If the suit really needs it, find a dry cleaner with a good reputation, and avoid using them more than a couple of times a year.

Hanging up your suit in the bathroom while you shower can help bring some moisture into the wool fibres, Mr Johnson adds, and helps smooth any creases.

If you're wearing your suit regularly, think about getting an extra pair of trousers, as they'll wear faster than your jacket.