I probably shouldn’t say this, what with fashion literally being my job, but the honest-to-god truth is that you can safely ignore about 98% of fashion trends and it won’t make you any less fashionable.

A sea change in how we dress only comes around every so often. Most of what the fashion industry calls trends are just the surface ripples that happen between these big waves. Sheer skirts, mesh shoes, cowboy hats, that kind of thing.

You can ignore pretty much everything else that has happened in fashion this year, except for one thing, which is that your jeans can’t be tight any more. A jean with a looser leg shape is the one change you need to have made to your wardrobe. OK, OK! Obviously I do realise this isn’t an essential in the literal sense. But it is essential if you want to be in the world looking and feeling like you know what year it is. And, since you are reading this, I rather think that you do.

But how big your jeans need to be is the main question. They don’t have to be as dramatic as the pair pictured here, at least not yet, so please don’t panic. The only non-negotiable is that you need to feel space between flesh and denim, from the hem at least up to mid-thigh. So the switch can be as low-key as swapping sausage-skin skinnies for a straight-leg jean, to start off with. But once you get used to the way a loose-leg jean feels on your body and looks in the mirror, you may be ready to take things to the next level.

There are three ways to go. The first is baggy all over, the second option is flared, and the third way is a barrel or horseshoe shape, which is what you can see here. Today – as you may have guessed from the photo – I’m putting forward the case for the barrel-leg.

Here’s why. Baggy-all-over jeans are, style-wise, arguably the most on-point, judging by the fact that this is the shape young people are mostly wearing. But the vibe of a big old baggy jean is deliberately scruffy. The way the hem drags along the pavement? That’s intentional. Youngsters dress like this because they want us to clutch our pearls. I know age-appropriateness is not supposed to be a style concept any more, but I do think scruffy is hard to do with charm north of 40. So the big old baggy jean? I’m sitting that one out.

Flares are tricky, now that jeans are bigger all over. A boot-cut or a kick flare was a manageable, bitesize way to do a flare when jeans were tighter. But if the top half of a jean is already loose, the flare gets enormous. To make baggy flares work, you need to lean into glamour: a high-waisted flared jean with a stretchy knit top and a platform sandal, say. Fabulous. But not the easy-to-pull-on look most of us want from our denim.

The barrel-leg jean, or horseshoe jean, balloons outward in a harem-pant silhouette, and tapers to a neat ankle. The ones you can see here are the Luna style by Agolde, in recycled denim, with a straight front seam that emphasises the crescent-moon silhouette of the leg. Whistles is a good place to head for sophisticated, easy-to-wear takes on this shape: I really like its authentic barrel-leg jean (£95), which is made in non-stretch denim – that’s the “authentic” part – meaning they keep their shape much better. Stretch jeans are great if you want them to mould to your shape, but if you want them to keep their own silhouette, go for non-stretch. Free People’s We the Free Good Luck Mid-Rise Barrel Jean (£88-£98) comes in every colour from pistachio to tie-dye bubble-gum pink.

The shape is … let’s go with eye‑catching, shall we? Not silly but bold. It might feel intimidating, but it is an efficient way of dressing, style-wise, because with a pair of jeans in this shape, your look doesn’t need much else. A close-fitting top that you can tuck in, and some simple shoes with a low profile – a ballerina flat works just as well as a pointy court – are more than enough. These jeans are the only dose of fashion you need.

Stylist’s assistant: Sam Deaman. Hair and makeup: Sophie Higginson using Sam McKnight and Nudestix. Model: Maria Diniz at Milk. Jacket, £49.99, zara.com. Top, from a selection, filippa-k.com. Necklace, £17.99, zara.com. Jeans, £300, agolde.com. Shoes, £320, aeyde.com. Earrings, £135, tillysveaas.com