Skirts have a reputation for being either the easiest thing in your wardrobe or the thing that sits in the back with the tags still on, depending entirely on whether you got the length and the waistband right the first time. I've had both experiences, sometimes with the same skirt, which tells you most of the problem is fit rather than the idea of skirts generally.
The ones that actually get worn pair with things you already own rather than things you had to buy specially. A plain midi with a jumper and boots is basically a uniform by October. A denim skirt does the same job as jeans but with a plain t-shirt tucked in and trainers, no further thought required. A black skirt, in whatever length you get on with, sits under a shirt for work and under a jumper for everything else, which is the kind of quiet usefulness that makes it worth owning more than one. If you're starting from nothing, I'd go for a midi in a fabric with a bit of structure, not too clingy, not too stiff, in black or a dark neutral, because it goes under or over more things than a mini or a maxi will and doesn't need the weather or your mood to cooperate.
Fit is where skirts quietly fall apart, usually at the waist or the hip, never both at once in the way you'd want. Sit down in the changing room, properly sit, not a hover, because that's when a waistband that looked fine standing up starts digging in or gaping. Walk a few steps too, a straight skirt that's slightly too narrow at the knee will announce itself immediately by refusing to let you take a normal stride. For anything with a side zip, check it doesn't pull or show gapping when you reach up, and for wrap or button styles, check what happens when you sit down and the overlap decides to have opinions of its own. Minis and A line shapes are more forgiving through the waist but less forgiving on length, so try the length sitting down as well as standing, because three inches can turn into something else entirely once you're on a chair.
The difference between a good one and a disappointing one usually shows up in the waistband and the lining before anything else. A proper waistband doesn't roll or curl after a few wears, a lined skirt doesn't cling to tights with static by eleven in the morning, and a zip that's sewn in straight won't pucker at the seam. Cheap satin looks fine on the hanger and sad in daylight, so check it holds its sheen without creasing the second you sit down.
Reach for a skirt whenever jeans feel like too much effort to think about and a dress feels like too much to commit to.