We collect from a very expensive hobby with one of a kind art pieces and other things we hold dear. So we get upset when we hear that a piece has been lost or damaged or destroyed. But it get worse when they are supposed to be covered by insurance for such cases.
What the post office will not tell you is that you can purchase insurance for ANY type of package within the USA BUT it is NOT covered UNLESS it is sent REGISTERED MAIL. The USPS has failed to mention this on their website and you will only find out by calling their 1800 number. Apparently, registered mail is under 'lock and key' but there is NO guarenttee that it will even get to its destination O_O;
A recent event in my area opened this postal (scam?) and I think its best for those who mail out thousands in cels

A man sent a check to a contractor in Queens from the Bronx via priority mail, (which should take 3 days MAX). The item was insured for I think $3000? as the check was around that much. Well, after weeks of waiting, the check went missing, the guy filed a claim and got back ONLY $30 and called the local news company

Packages leaving the USA are covered automatically for priority and express shipping, and additional insurance can be purchased to cover the item(s) total value. so international collectors shouldnt worry.
Be sure to call the 1800 number if you will use insurance!! As most of the postal workers will not even know about it.