Fashion show finales follow a familiar rhythm: after the models march along the catwalk for a last hurrah, the designer comes out to take a bow. Their demeanour is often telling, an indicator of their attitude to the collection they've shown – are they a bag of nerves, or grinning from ear to ear?

Also noteworthy is the look they choose to take their bow in. Are they even wearing their own work? One of the most celebrated designers of our time never wears his own designs. Karl Lagerfeld may create the occasional menswear look at Chanel and he designs a whole men's collection for his eponymous label but he has long been a customer elsewhere: Dior Homme.

Lagerfeld started wearing Dior Homme when he was in his late 60s, shedding 41 kilograms to fit into the skinny styles of the label's then designer, Hedi Slimane. Lagerfeld has stayed loyal to the brand ever since, even after Slimane, now creative director of Saint Laurent, quit in 2006. And although the label is known for its emphasis on youth, Lagerfeld, now in his 80s, remains one of Dior Homme's most visible clients.

Raf Simons, meanwhile, Dior's creative director of womenswear, is partial to Prada: his presence in the documentary film Dior & I (2014) is most clearly announced via his distinctive studded Prada sneakers and he often takes his catwalk bow in a head-to-toe Prada look. For his first Christian Dior ready-to-wear show he wore a vintage denim jacket with red stripes by Austrian designer Helmut Lang.

And yet many designers do wear their own work, especially if the brand carries their surname. Editors scan the wardrobe of Miuccia Prada for clues to her latest collection: is she feeling utilitarian, elegant or purposefully off-kilter? When Donatella Versace takes her bow, she often wears a look from the collection she's just shown – for autumn/winter 2015, it was a pinstriped, flared pantsuit. And even Simons has worn pieces from his own label collaboration with Sterling Ruby.

So if the name is on the label, does it mean the clothes will always be on the designer's back? Not necessarily. "I've never been into wearing clothing with my own brand name inside," says Jonathan Anderson, designer behind JW Anderson and now creative director of Loewe. "I find it odd and arrogant."

UNIFORM DRESSING

Anderson's own wardrobe is a familiar uniform: crewneck sweater, faded blue jeans, Nike sneakers. It's entirely opposite to the menswear looks he creates for his own label's catwalk presentations, which have included bandeau tops and frilled shorts. He seems to favour a clean-palette approach: keeping himself neutral so as to not deflect from his experimentation elsewhere.

This kind of wardrobe is common among fashion designers. Jack McCollough and Lazaro Hernandez of Proenza Schouler appear to have no desire to create menswear for themselves or others, dressing instead in a similar style to Anderson: crewnecks, polo shirts or button-downs, usually with jeans and sneakers.

Mary Katrantzou, meanwhile, recent winner of the 2015 BFC/Vogue Designer Fashion Fund, may have built her business on print and embellishment but she is usually found in a black knit dress by Azzedine Alaïa. Alaïa himself has perhaps the ultimate clean-palette wardrobe: for decades he has worn black cotton Chinese pyjamas, fastened by simple floral buttoning.

Each of these designers has a successful business with its own clear signature. So maybe it doesn't matter if they don't wear their own clothes. And yet when designers do, it can be so seductive. Men buy Tom Ford because they want to be like Tom Ford. Women buy Céline because they want to look like Phoebe Philo. Stefano Pilati, creative director of Ermenegildo Zegna Couture, is often said to be his own best model; Rick Owens, in his long draped vests and baggy shorts, is the perfect ambassador for his own alternate universe of otherness.

The style of Roksanda Ilincic is synonymous with her own brand. "I create pieces that embrace the female form," she says of her bold colour palette and silhouette. "Being a woman means I'm able to feel and test those things on a personal level … I tend to favour long hemlines and nipped-in waists, with interesting shades and textures, pared down with simple basics and outerwear." Does she ever wear anyone else? "Of course! Black polo necks from Wolford are an absolute staple and in winter I am rarely without my favourite black cashmere coat by Prada, which is on permanent loan from my husband."

It seems like an industry divided between designers who wear their own work and those who don't. But sometimes things change. Backstage at Loewe earlier this season, Anderson said: "With Loewe, I have a detachment. I wear a lot of it. Now I'm more, 'Does this work?' I've got a bit of a love back for fashion."

Two months on, his interest in wearing his own designs has grown still further. He is the cover star of the new issue of menswear biannual magazine Fantastic Man, posing in a slash-fronted sweater and leather tie trousers. The pieces are both his work from current season Loewe. Womenswear. In for a penny, in for a pound.Read more here:www.marieaustralia.com/formal-dresses-2015 | www.marieaustralia.com/long-formal-dresses