I bought my first pair of pleated trousers thinking the pleats would stay put, neat little folds running down from the waist like they do on the hanger. They don't. After a full day at work, sitting, standing, crouching to reach a shelf, the pleats soften and shift, and by the time I'm walking home the front has a looser, more draped look than it had at nine in the morning. That's not a flaw, it's just what happens, and nobody in a shop mentions it because on the rail they always look pressed and perfect.
Before you buy, check the rise properly, because pleats sit at the waist and if the rise is too low the fabric bunches awkwardly over the hips instead of falling in a clean line. Sit down in the changing room, not just stand in front of the mirror. A good pair keeps its shape across the lap without the pleats pulling tight or the waistband digging in when you fold forward. Check the fabric weight too, because anything too light clings and loses the structure that makes pleats worth having in the first place, and anything too heavy can feel stiff by midafternoon.
They don't sit well with anything already bulky up top. A chunky jumper tucked in adds volume on volume, and you end up looking wider through the middle than you actually are, which defeats the point of a tailored trouser. I'd also avoid pairing them with very fitted tops that have their own strong shape, the two silhouettes argue with each other rather than sitting together.
Where they genuinely work is anywhere you want to look put together without trying hard, an early autumn work day, a long lunch, travelling somewhere you'll be sitting for hours and don't want to arrive creased in the wrong way. They carry a long sleeve top or a simple shirt well, and a longer line coat over the top looks tidy rather than overdressed, which is useful from September right through to the colder months.
They're the wrong choice if you're short in the body, because the extra fabric at the front can shorten the leg line and make the whole thing look heavier than intended. I wouldn't wear them for anything involving a bike, a train platform sprint or a day on your feet from start to finish, the fabric moves with you but it isn't built for speed. And if you're wearing a longer tunic or layering top over the waistband, you lose the whole point of the pleat, so keep tops shorter or tucked.
A good pair of pleated trousers makes an ordinary day look like you planned it, even when you absolutely didn't.