The thinner belt is trending more than wider, statement belts. However, I love a medium to wider belt with jeans. It depends on what look you're going for. I'd wear my most favorite jean to the boutique. Also, think about the outfit you wear most with jeans. Is it a tee? Is it a flowy top? Then wear that outfit to go belt shopping. Better yet, wear layers so you can try the belt in a casual vs professional vs evening look, e.g. a lacy cami under a tee, layered under a blazer.