A fashion editor did something rarely done in her profession: instead of recommending a bag, she asked her colleagues what they actually need from one. The result is a list with no connection to trends and every connection to what a working day actually looks like.

First: how much goes inside

One of them gives the list unfiltered - it has to take a laptop, a planner, gym kit for after work, a make-up bag and a lunch box. Another wants the opposite, a medium size, precisely so that empty space does not get filled. Both are right, but for different lives. What they all agree on is compartments: at least one zipped pocket for the valuables, so nobody is hunting for a phone among keys that are scratching its back.

Second: zip or button

Here the editors fall out. "My perfect bag is a tote with no zip, just one button, because I stuff it so full it does not close anyway," says one. The other is categorical: "A zip is mandatory. I am a disaster and things fall out of it when there isn't one." Some models have both, which is a solution of the sort that says: we do not want to decide.

Third: material and colour that do not give up

Leather or nylon. A dark colour, and not for elegance but for arithmetic - a light bag rubbing against dark clothes every day starts to show you why it was expensive. The recommended tones are burgundy, forest green and chocolate brown, because they carry both summer and winter.

Fourth and fifth: holds its shape, holds on the shoulder

A bag that collapses into a sack the moment you set it on the floor does not look professional, however much it cost. And the handles must take being carried on the shoulder or across the body without sliding. That is all of it.

The list of recommended models runs from 135 euros for a nylon Longchamp Le Pliage, through 149 for Charles & Keith, to 650 for a leather Demellier. In between there are ones at 269 and 315 euros. If you read the list of requirements, you will notice something interesting - not one of the five requirements needs 650 euros. All five are met by the 135-euro bag as well.

That is usually the point where the fashion industry stops explaining. It hands you a functional list, then shows you a price the list does not touch. You pay the difference for something else - and that is entirely legitimate, as long as it is called by its own name.