Karl Lagerfeld. Steve Jobs. Barack Obama. Mark Zuckerberg...these are but a handful of successful men who've attributed a small portion of their success to having a 'work uniform'.

Although society grants men the luxury of dressing plainly with no questions asked, it hasn't always been so kind to women in the workforce (just ask any female politician), however, there are theories to suggest it may well be one of the hidden keys to career success. Why? It all comes down to a concept known as 'decision fatigue'.

With the average person said to make roughly 35,000 choices every day (Which staffer should I hire? Skim or full-fat? Should I bring an umbrella today?) and women facing more pressure than men over appearance-related decisions, it's thought that eliminating the need to come up with a new outfit every day can allow the brain to prioritise other work-related decisions.

In short, it's supposed to save your cognitive capacity for creative thinking where it really counts.

Theories around decision fatigue aside, it could well be that the decision (yet another one) to repeat outfits or choose a signature look simply readies you for a day of work, the old "dressing for success" adage, by creating a daily ritual to mentally enable success.

And it's not only powerful men who've adopted this mindset, with many female founders and celebrities citing the work uniform as a fundamental part of their daily life.

Here, we take a look at 10 famous women who've developed their signature work look over the years and exactly why they love it.