India, July 21 -- I travel a lot for work and holidays, and if there's one packing question I get asked all the time, it's this. Cabin backpack or trolley bag for a short trip? You thought I was going to pick one and declare it the winner? Not happening.

The real answer is much simpler. Ask yourself two questions. What is the purpose of your trip? Where are you headed? That is the only formula that has worked for me after years of catching flights, taking train rides, going on road trips, and taking weekend breaks. There isn't one perfect bag. There is only the right bag for the trip you're taking.

A cabin backpack earns its place when I know I'm going to be moving around a lot. If my itinerary involves long walks, changing buses, climb...