We’ve been backpacking the world for 7¬†months now and this is what we’ve learned.
First, here’s the bag we recommend you buy:Osprey Porter Travel Backpack Bag, Black, 46-Liter
  • Wheels break.
  • Hard suitcases don’t fit and cannot be squished to fit.
  • You shouldn’t carry enough stuff to have to need wheels.
  • If one bag costs $30 dollars more and is a little better, spend the money.
  • Make sure it fits comfortably-try it on in the store.
  • 47 liters is enough space to keep enough clothes and anything else you need to travel the world.
  • I’m glad I didn’t get anything bigger, because I’d hate to have to carry anything else.
  • I over-packed as it is now with 47 liters.
 
If you are travelling for 10 days, take 3-4 days of clothes and do laundry. It’s easier than carrying 5 days of clothes.