The question I get most about stretch jeans is whether they’ll go baggy by the time you’ve sat through a shift or a train journey, and the honest answer is some will and some won’t, and it comes down to how much elastane is actually in the mix rather than the cut. Anything under about two per cent barely moves. Go higher and you get that softer, almost leggings-like give, which feels brilliant at nine in the morning and can look a bit deflated at the knee by six.
Worn regularly, a good pair settles into you within a few weeks rather than fighting you the way rigid denim does. The fabric gets a particular give at the hip and behind the knee where you actually bend, and it holds that shape rather than losing it completely, which is the whole point. Wash them inside out, cold, and skip the tumble dryer if you can stand the faff of drying them flat, because heat is what kills the stretch long before the colour goes. I ignored that for about a year and ended up with a pair that fit like a sock with ambitions. Cold wash, air dry, they stay closer to new for twice as long.
What they don’t sit well with is anything else that’s already doing the stretching for you. A ribbed bodysuit or a very clingy jersey top on top of soft stretch denim reads as all one texture, nothing structured to break it up, and the whole outfit goes a bit shapeless. I’d put something with more body up top, a proper shirt, a stiffer jacket, so there’s one part of the outfit holding a line while the jeans do their own thing underneath. They also don’t love being paired with heavy, boxy boots if the leg is already on the slouchier side, it just adds bulk on bulk.
Where they properly fall short is anywhere you need the fabric to hold a sharp line all day, a formal office with a dress code that wants tailoring, or any kind of work where you’re kneeling and want denim with real resistance rather than give. Stretch denim isn’t that. It’s comfort first, and the trade off is a fabric that will eventually lose a bit of its recovery no matter how carefully you treat it.
Months in, the change is gradual rather than dramatic. The knee softens first, the inner thigh can pill slightly where it rubs against itself walking, and the colour fades more slowly than you'd expect from a stiffer denim because there's less actual cotton taking the hit. By the end of a year they're looser, softer, a shade paler, and genuinely more comfortable than the day you bought them, even if they'll never look quite as sharp again.