I have the aluminum cabin small and love the size. It can fit everywhere and and is so easy to handle. I used mine for a 3 week trip.

Actually, the size of luggage doesn't determine how long your trip is. Decades ago I used to pack large suitcases for one week trips and had no clue about minimizing. Thereafter, I started traveling the Rick Steves way or even less than that. So my first test trip was a 6 month trip with just a carryon size backpack (ebay mother lode). You just wash your clothes. Since then, I've traveled a multitude of ways, but the most convenient is traveling with only a small piece of luggage that can go anywhere.