The thing nobody mentions in the shop is what happens to the back of the heel after about three weeks of actual walking, not shop-floor shuffling. Cheap loafers crease across the toe within days and the leather (if you can call it that) starts to gape at the sides where your foot flexes, so you end up with a shoe that looks fine sitting still and slightly collapsed the second you're mid stride. A good pair creases too, but it creases like a leather jacket does, in a way that looks earned rather than knackered.
Before you hand over any money, bend the shoe in half in your hands. If the sole folds with no resistance and the inside smells like a swimming bag, that's your answer regardless of how nice the stitching looks. Check the heel stiffener by pressing the back of the shoe between finger and thumb, if it folds flat and stays folded, it won't hold your foot in place by month two. On sizing, loafers are one of the few shoes where going true to size rather than your usual half up is usually right, because they're not meant to have the same give as a trainer, and a loafer that's too big will slip at the heel on every single step, which is the single most common fit complaint I hear and the one that ruins them fastest. If you've got a higher instep, try before you buy if you possibly can, because some will pinch across the top in a way that only shows up after sitting down for an hour. They don't get on with skinny cropped trousers that stop right at the ankle bone, it's an odd, slightly dated combination that makes your leg look chopped off, and they're not the shoe for anything involving standing on wet cobbles, the soles are rarely built for grip. Where they genuinely shine is office days through fairly cold weather with proper socks, a Saturday where you want to look like you tried without trying, and the stretch from early autumn right through to when it's warm enough for bare ankles again, after that they start to feel like you're wearing the wrong season on your feet.
Tomorrow I'm putting mine with slightly wide leg trousers that break just above the shoe, a plain jumper, and a coat I can actually move my arms in, because the whole point of a decent loafer is that you stop thinking about your feet by nine in the morning.