Most people in the trades have a bucket, box, or milk crate that they use to carry loose items from the van to the jobsite.
When empty, your milk crate takes up space and you're probably tempted to fill it with stuff when you aren't using it.
A folding box or crate takes up a lot less space when you don't need it, and you won't be tempted to fill it with junk when you're not using it.
