So how do you pack for 12 months away? With much difficulty I can tell you!
My method was to keep halving everything I really would have liked to pack (although agonising over every little thing… this Tshirt or that Tshirt? This pair of shoes or that pair of shoes?) to get closer to (what we thought was) the maximum weight… finally ending up discarding things at the hotel in Sydney before heading for the airport… only to find out that we were allowed the full USA allowance of 2 x 23kg bags each for our entire round-the-world trip (and not just a max of 23kg which is the Asia/Europe allowance.)
Of course it’s normally a good idea to pack light when traveling but we were basically moving to France (albeit stopping along the way) and it would have been good to be able to take a few more things, especially kitchenware. Mind you, it was fun picking up a few bargains in Asia and of course then we needed extra suitcases to pack them in!