The first thing I do is grab the ankle cuff and give it a proper tug. If it's thin and loose, it'll bag out by lunchtime and you'll spend the day hoicking them back up, which is no way to live. A good cuff has a bit of resistance to it, enough that it sits close without digging a line into your skin. Same with the waistband, I want to feel some structure in there, not just a thin strip of elastic that gives up after one wash.
Cotton joggers earn their place from the back end of autumn right through to early spring, when you want something that keeps the heat in but doesn't make you look like you've given up entirely. They're brilliant for a cold walk, for sitting about a house that's never quite warm enough, for travelling, for any day where the plan is comfort and nothing more is being asked of you. Where they come unstuck is high summer, cotton gets heavy and damp fast and clings in a way that isn't pleasant, so I leave mine in the drawer once the weather properly turns. I'd also steer clear of pairing a heavier cotton pair with anything equally bulky up top, a thick cable jumper on top of thick joggers and you've built yourself a sort of soft furniture situation. One or the other gets to be chunky, not both.
They wear well if you treat them a bit like you would a good jumper rather than gym kit. Wash them inside out, on a cool setting, and resist the tumble dryer unless you fancy watching them shrink an inch at the ankle, which happened to a pair of mine and they never forgave me. Cotton pills eventually, that's just what it does, but a decent weight of fabric pills less and slower, so the cheap thin ones will look tired within a few months while a properly made pair can go a couple of winters looking much the same. The knees go baggy before anything else does, that's the tell of a pair that's been worn into the ground and loved for it, no shame in it at all. Dry them flat or on a low heat and they'll keep their shape far longer than the label probably promises.
Would I still want to wear these after they've been washed forty times and sat in a drawer through a whole summer, or are they only good for the first few wears before they go the way of most things bought in a hurry?