Many many things about moving containers
Portable storage units are weather safe so there are no fears about getting things wet or moldy. This makes it easy to get any nonessential items packed up and out of the way first-- and it's a lot more convenient than having 100 boxes underfoot while you pack. When the real moving day comes, you already have the less necessary things packed way in the back and you can add the more day to day stuff in. The portable storage company will send a truck to pick up the unit and deliver it to your new doorstep. When you're all one with your unpacking, you simply call them up and have the portable storage container removed.