I already talked about the advantage of putting things in pockets to have your hands free to open doors etc (see Hands free).
Now, as I had to carry a lot of luggage in the last weeks and as I am changing flat in the next weeks I see that a free hand is wasted efficiency. Currently I am living at the third floor without elevator so if I would try to keep a hand free I would have to go double the times up and down. This does not mean that the "hands free" idea is now forgotten - no - I try to put everything into boxes and pockets as much as possible. More, I can put one into the other more "available capacity" still there.
So the "Don't go empty" idea is used in combination but even more:
You can put a backpack on your back and another one on your belly. In addition to that you can hang backs diagonal over your shoulders.
Butt attention: You have to take care that all together is not becoming too heavy. Take this into consideration when planning your way to or from the car. Combine heavy and lightweight things.
When you stoop remember to go down in the knees and not by bending your back!
Related Posts: Hands free, Don't go empty