I had to learn very quickly how to streamline my packing once I started traveling around the world as a roving scuba diving instructor. Since I had to be the one throwing my bags on and off buses and ferries and dealing with airline weight restrictions (which can be difficult to manage once you take into account how heavy scuba equipment is), I became much better at packing well. Quality, not quantity!
Layovers suck. Short or long, it doesn't matter, layovers are not fun. And even if you think that a layover will be short, there's a good chance that your transport will be delayed or cancelled, so it's important to be prepared for any transportation crisis.