Denim skirts went through a rough patch somewhere in the 2010s, all stretch and distressing and that horrible low rise that only worked if you had nothing to tuck in. The newer crop is better: proper rigid or barely there stretch, longer midi lengths alongside the minis, and a cut that sits on or above the natural waist rather than fighting it. It feels like a genuine improvement rather than a trend doing a lap.
Good denim softens with wear in a way that cheap denim just doesn't, it goes thin and grey at the stress points instead of moulding to you. Wash it inside out, on a cool cycle, and not after every single wear, denim actually prefers to be left alone for a while. Button and zip flies hold their shape far longer than the elasticated waistbands that start gaping by the third wash. What it genuinely struggles with is anything else heavy in the same outfit, a chunky jumper and a stiff denim skirt together can make you look like you're wearing a barrel, so balance it with something softer on top, a fine knit or a blouse that skims rather than piles on bulk. It also doesn't love being paired with another denim piece unless the washes are clearly different, matching mid blue on mid blue just reads as an accident rather than a choice.
This is a three season piece more than a winter one, brilliant from spring through early autumn with bare legs or thin tights, and it works equally well dressed down with trainers for a weekend or dressed up with boots and a smarter top for something in the evening. Where it gets weaker is deep winter, when a skirt that doesn't flex much with layering underneath starts to feel impractical rather than stylish.
The difference between a good one and a bad one is mostly in the weight of the fabric and what's underneath it. Pick it up and feel it, a denim skirt that feels thin and flimsy will crease badly and lose its shape within weeks. Check the stitching on the seams, uneven or loose stitching there is usually the first thing to go. Buttons should feel solid rather than light and plasticky, and a proper rivet at the pocket corners is a small sign that someone thought about how it would hold up, not just how it would photograph on a hanger.
Even a well made denim skirt has a limit though, it will never move the way a soft fabric skirt does, and if you need something that packs flat or drapes rather than holds its shape, this isn't the piece for that.