Races, weddings, festive gatherings: they come on thick and fast this time of year. Which means so are the invitations, and all of their perplexing dress codes. And codes they are, because who – aside from the etiquette arm of the MI5 – could actually decipher what “beach chic” or “a touch of glam” means?

My least favourite is “dress to impress!” (Impress who?) And “bring your dancing shoes!” (Is this a literal instruction? How am I meant to fit a pair of sneakers or thongs into an evening clutch?)

There is much potential for bad decorum. For example, at which point does a tie become mandatory instead of a maybe? Do I really need a floor-length frock for a black tie event? And if Kanye can wear Nikes with a tux, does this mean I can too?

While dress codes have evolved and also relaxed over the years – in no small part due to celebrities flouting convention on the red carpet – they’re often still specified, and following them can help you feel comfortable (and demonstrate respect) in a range of social settings.

It can be quite a minefield – here’s a guide to the classic dress codes.

Casual

This is a popular dress code for wedding recoveries or events outside the city. Free and easy, you’d think it’d be hard to get wrong. But the hosts have bothered to put a dress code on the invite for a reason, so there’s some expectation of effort. Maybe a buttoned-down linen shirt with jeans or chinos, smart sneakers or boat shoes, and a pair of Wayfarers, or some kind of romper with natty plimsolls and stacks of bangles. Basically, quite a lot of effort to look effortless.

Business casual

If my husband and I end up in Splitsville, it will largely be due to irreconcilable differences over business casual. Every casual Friday we experience the same pain caused by his inability to outfit himself in a way that satisfies the code. Granted, much of this stems from the lack of a common definition – the word “business” is so indeterminate these days. At a techy start-up it might mean dark jeans, a simple tee and trainers, but at larger corporates it probably calls for chinos, a collared shirt and leather Oxfords or loafers. Dresses and skirts should be conservative, but heels aren’t necessary. Keep a grandad collar shirt with slim tailored pants in mind as a backup.

Smart Casual

Slightly more polished than biz-cas, blokes might consider adding a sports coat or blazer, though a tie isn’t necessary. Gals can wear pants, dresses or skirts with more personality, either with or without heels. Elegant boots are perfectly acceptable, or maybe an espadrille or bejewelled sandal in the summer. Pedicures are advised.

Cocktail (or Semi-Formal)

A synonym for “dressy”, this category is meant to bridge the hours between day and night. Not too relaxed, but not too prissy either. Lads should wear a suit, either with or without a tie, and gals can go for shorter party dresses (midi and ankle-length dresses are also appropriate), or chic separates with heels or pretty flats. A hint of thigh is fine. These days you may see smart boots and fresh designer sneakers paired with cocktail attire, but if you’re a stickler for etiquette, then it’s strictly no sneakers, denim or boots (even if the weather’s bad), and no stockings with open-toed shoes.

Lounge Suit

How many times do WhatsApp groups debate the parameters of the lounge suit before an event? Feels like groundhog day every time it resurfaces. In basic terms, it’s a two-piece suit with a tie for men (cotton or linen is fine in warmer months), and either tailored suits or dresses for women that fall on or below the knee. (If the event is out of town, a pretty floral or printed dress is appropriate.) Heels or fancy flats are preferred (boots are definitely off the table), and ensembles should be elegant rather than flirty.

Black Tie

For gents, black tie calls for a tuxedo or a dinner jacket (usually black, with a silk lapel) and matching pants, with a self-tie bow tie (there are YouTube tutorials for the latter – allow 45 minutes for the average noob). Waistcoats and cummerbunds remain optional, but pocket squares and cufflinks are encouraged. Signs of heathenness include clip-on bow ties, and bow ties worn with any type of suit that is not a tuxedo or a dinner jacket. (These days you may see stylish rule-breakers don an elegant skinny black tie instead, or even a dress shirt that buttons to the top without need for either.) Women can opt for slim-fit tuxedos or longer evening gowns paired with finer jewellery. (In Australia, where red carpets are rare, hems have been known to rise.)

Morning dress

A popular challenge on Derby Day, this dress code demands morning suits (that is, a tail coat with a waistcoat and formal pants). Top hats are optional, though obligatory at some events such as the Royal Ascot in London. Formal day dresses should be paired with hats, and if the crowd is stuffy, wear pantihose. Morning dress is not appropriate for events beginning after 6pm – that would be white tie.

White Tie (or full evening dress or dress suit)

Unless you’re a conductor, a royal or a guest at a Nobel Prize ceremony, it’s unlikely you’ll ever need to wear White Tie. (It was a fairly routine formal dress code up until the mid-20th century, when black tie became the formal standard-bearer.) But just in case you nab yourself an invite to an Oxford University ball or a state dinner in Washington DC, prospective princelings will need all of the following: a white self-tie bow tie, white shirt with wing collar, braces, white waistcoat, black tail coat, and black trousers with two trim stripes. Waitstaff wear a black bow tie – hence the crucial distinction for gents to wear white.

White dresses, however, are reserved for debutantes. Floor-length evening dresses or ball gowns in any other hue are acceptable, and should be paired with long gloves to cover the arms. Think Lady Mary vibes from Downton Abbey – sumptuous fabrics, elaborate adornments, all painfully posh. If you’ve got a tiara lying around, this is the time to wear it.