A black jacket has a reputation for being the easy choice, the thing you buy when you can't decide, and most of the time that reputation is earned. I land firmly on the side of having more than one, because a black jacket is never really one item, it's a decision about how smart or how scruffy you want to look that day, made before you've had your coffee.
It sits over almost everything you already own without an argument, which is more than you can say for most colours. Jeans and a plain top, a dress that's slightly too summery for the weather, a work outfit that needs one more layer to feel finished, it all works under black without you having to think. It's good from the first properly cold morning right through to the kind of grey bank holiday where nothing else feels right, and it does a quiet job at anything from the school run to a dinner you didn't have the energy to dress properly for. The one thing it struggles with is high summer, when every black jacket in the country suddenly looks like you've given up on the season, which, fair enough, sometimes you have.
How it wears depends entirely on what it's made of, and this is where a lot of people get caught out buying on colour alone. A cheap polyester one will go shiny at the elbows and cuffs within a year, especially if you're the sort who leans on tables or carries bags on one shoulder, which is most of us. Wool or a wool blend holds its shape and its colour far longer, and a decent cotton or denim jacket just softens nicely with wear rather than looking tired. Whatever it's made of, wash it less than you think you need to, air it instead, and keep it off direct heat when drying, because black fades to a dull grey brown faster than almost any other colour when it's mistreated, and there's no fixing that once it's happened. A soft brush now and then keeps wool ones looking new far longer than any dry cleaner's bill.
On shade, go for a true flat black rather than anything with a blue or green cast to it, because those undertones only show up under certain lights and then you're stuck trying to match it to black trousers that are a different black entirely. Matte finishes are easier to live with day to day than anything with a sheen, which shows marks and creasing far more readily. Reach for a black jacket on the mornings when you haven't settled on an outfit, on the days you need to look like you tried without having tried too hard, and through every month that isn't actually hot.