Have you ever wondered how trends are born and what determines their longevity? It is impossible to formulate an all-encompassing theory, but having worked in the fashion industry I have been exposed to this phenomenon more than most. It is a complex process, but here are some of the elements.

One big factor in the birth of a trend is fabrication. This is where the supply chain starts, because without fabric you can’t make a product. Fabric producers need to predict the trends, or better yet, determine them in order to know what to produce for future seasons. So the big fabric mills host trade shows like Premiere Vision, which takes place in Paris every September. Designers attend these shows to get inspiration for their upcoming ranges.

Designers also visit top trend houses like Promstyl to get the creative juices flowing. They document their inspiration and are also very much inspired by what they see on the street. Every city has fashion pioneers who are creating bold new outfits that challenge the current norms, and even making their own creative clothes. Street style is a major source of inspiration, so it’s possible that you could be setting the next big trend without even knowing it.

And then there is popular culture. Trends in other aspects of our lives are influencing designers all the time — up and coming bands, new movies and television shows, literature, technology.

Having combined all this inspiration with their own creative energy, top designers show their resulting collections at Fashion Weeks all over the world. They typically do this twice a year – in Spring and in Autumn. The shows are scrutinized by the retail industry and press. It’s then up to fashion buyers, editors of fashion  magazines, retail management and mainstream designers who directly work with manufacturers to pick and choose the styles and trend direction for retail stores. Some trends barely change and what you see on the catwalk is what you’ll see in stores. Some trends are adapted or watered down to look more “normal” for everyday style. And some trends never filter through to retail stores. There are also trends that take a couple of seasons to filter through so not all hope is lost after rejection the first time round.

Once trends hit stores, consumers have a say in the matter too. If they like what they see, the trends sell well. If they don’t, trends get marked down as soon as possible. Top selling trends are repeated the next season and often become mainstream basic lines. So you as a consumer have the power to keep a trend alive and see it become a mainstream success.

But there is still so much that is unexplained. I always wonder how it happens that there is often such consistency across designers in the new trends we see emerging on the runway. Who decided that skinnies should come back into fashion, or that hemlines should be raised, or that turquoise should be the next big colour? Is there a top secret meeting somewhere to ensure that strong shouldered looks make a comeback? How do top trend houses decide that grunge is back or that safari themes are all the rage?

Or perhaps there is a big element of chance in the birth of a trend. Rather than something being consistent across designers because it is a new trend, perhaps something is a new trend because it happened to be consistent new theme on the Fashion Week runway.

If you work in the industry, I’d love to hear any insights you can offer on this elusive process. As a consumer, do you have any theories of your own on the birth of trends?

Well ladies, you really surprised me with your responses to our recent poll on Flats versus Heels. Team Heels was the favourite in a clear majority. So I’d like to take this a little further by exploring the specific heel height that is your favourite.

For this exercise, anything higher than an inch and a quarter is considered a heel. Anything lower than that is a flat.

I’ll go first. My favourite heel height is between 1.5 and 2 inches. If the shoe is extremely comfortable, I can charge around town in heels this height, no problem. I also wear heels as high as three inches, but they are relegated to scenarios where I am sitting most of the time. No platforms and nothing over three inches. Over to you.

Today’s post is written by my wonderful sister-in-law, Keri, who works full time as the Supplements Managing Editor for a London-based magazine. Keri and I go back 22 years. We were university residence flat-mates and good friends before she married my brother Hugo, 15 years ago. Hugo, Keri and their 11 year old son Seb came out to visit Seattle recently and we had a ball. Keri has always had a great sense of style, an obsessive love for handbags and LOVES to shop. Needless to say I get on well with my sis in law! Keri and I had a wonderful time shopping the NAS.

I do consider myself particularly lucky to have such a stylish and talented sister-in-law in Angélique, and have always relished our 9-hour marathon shopping sessions together on her visits to us in London, so I was not going to pass up the opportunity to do the same when visiting her in Seattle, especially as our visit so fortuitously coincided with the Nordstrom Anniversary Sale.

The first thing to get my head around was the fact that this was not an end-of-season sale of odd-sized remnants and unpopular summer lines, but drastic reductions in new season clothing as it hit the shelves – unheard of in the UK! The bonus was that it was autumn (fall), my favourite season. But this was not going to be a complete walk in the park as I had decided that having hit the big 4-0 a few months back my style needed a bit of a revamp, and I needed to be nudged out of my matchy-matchy comfort zone. I had told Angélique her mission was (1) get me into dresses (I did not possess a single dress) and (2) get me into leggings (a look I have never felt confident enough to pull off). I did hint that I was not averse to having my boundaries pushed a little, but that tucking boots into pants and baring upper arms might be a step too far for this voluptuous hourglass …

Coats and jackets were the first port of call – Angélique pounced upon a rich teal Steve Madden wool coat for me with a cheeky flounce at the back, and before I realized what was happening I was in a red Michael Kors trench and totally besotted. A biker jacket was definitely on the list, but leather or pleather? In the end it was about the look and fit and pleather convincingly won the day with an uber comfortable and buttery soft Gallery jacket. A blazer was also on the cards. Pin-striped was my first choice, but it was the flattering front vertical panel of a black Halogen blazer that won me over. Then we moved on to pencil skirts – a black and goldy olive joined the gang.

Tops next and we started piling up a huge assortment to try on. I have always admired Angélique’s ability to survey the rails and hone in on just the right pieces. She knows my taste and what suits me, but she always surprises me by picking things I would never usually go for, and I end up not only with a fabulous new look but also a stylishly broadened mind!

The handbag department is a dangerous area for me, and it was with great restraint and much regret that I passed it by. Back in London I do have more handbags than years I have lived on this earth and I had to prioritise. However, we did detour into shoes and with my incurable weakness for wedges, Angélique had no difficulty in getting me into a pair of chestnut Steve Madden Maryn boots, which I know are going to get a lot of mileage!

Our selections were swiftly whisked away and arrayed around a waiting changing room by our efficient, helpful and charming sales assistant – all part of my American shopping experience (and somewhat different from what I am used to in the UK). We grabbed some leggings, knits, waterfall cardigans (black and my favourite pinky purple colour) and a couple of (sleeveless!) dresses en route, and Angelique slipped in some straight-legged Kut from the Kloth jeans (a departure for this boot-leg devotee) and black Ponte pants (described as leggings). And then began the fun of trying it all on and having Angelique work her magic.

With the constraints of budget and baggage allowance lurking in the back of my mind, I was somewhat relieved that we did have something of a ‘no’ pile, alongside the not inconsiderable ‘yes’ pile, but what amazed me was the number of different outfits Angélique could create out of just a few items. Yes, she did get me to wear my boots over those Ponte pants, dresses and leggings have been acquired and assimilated and the boundaries have definitely shifted. But what greater endorsement do you need than your husband telling you that your new look makes you look younger!

Nordstrom items pictured in this post (affiliate links):

• A — Steve Madden Maryn Boots
• B — Halogen Seamed Knit Skirt
• C — Halogen Drape Neck Dolman Sleeve Sweater
• D — Gallery Pleather Biker Jacket (in store)
• E — Steve Madden Teal Tiered Coat (in store)
• F — Kut from the Kloth Skinny Jeans
• G — Semantics Black Blazer (in store)
• H — Kenneth Cole New York Leggings

I wear both styles, but tend to wear my skinnies more often for several reasons: no heel height issues, no wet hems in the rain, I love tucking them into tall boots and they look super under tunics or short dresses.

I still wear bootcut jeans regularly though, and especially enjoy wearing them with cowboy boots and heeled booties. It’s an elegant and classic silhouette that I think I’ll always sport. But for the sleek and practical reasons I’m siding with Team Skinnies.

Whose Team are you? Tell us why. Do you think you’ll swap teams in the future? No batting for both sides!