If you mail anything via USPS, make sure it's something that you have a receipt for and then insure the box.
I recently recieved the front of a cardboard box (the USPS box-cut it off and mailed it back to me with a form to fill out) claiming that all of my items were "lost"... yet the box was still intact but not one item was ever mailed back. Odd, I had no idea that the USPS's mail conveyor was suspended above a small black hole...
I've used the USPS before and never had this problem, so I assumed that it was a crazy fluke accident. I was in the middle of a cross country move and the USPS was the cheapest option for mailing stuff, so the next packages I mailed (DVDs, books I acquired over the years, old family photos, etc.), I insured. This time the packages were ripped open in several spots as well as taped up where the box was completely ripped down the center. When I inspected the contents, several items were missing. Looks like someone literally kicked a hole in the box and was like; "let's take a looksy at what's inside" ...then continued to have at it like a caffeinated kid with a piñata.
Here's the catch... since I didn't have receipts for these things: family photos, vintage books, etc. ...ya know, just things that have taken years to acquire, the USPS did not reimburse me for the package. That said, if you're traveling cross country and thinking of shipping things to yourself, ship clothes and take all of your irreplaceable items as carry on.
If you want to read more horror stories about damaged and lost USPS boxes, just google USPS "customer experiences" with claims made for lost items. read more