Usually purchasing additional insurance for your courier package is not required as the items are tracked all the way to your destination but if in case your package does gets lost in transit, you can always claim for it even without purchasing insurance. The reason is that because the package should be sort of guaranteed to arrive. They may not refund you the full value of the item lost but some portion value of it.
In my case, i send a package from Canada to India using UPS company and i paid for the express post service which was supposed to arrive in three days time. It was a mistake and worst experience because the package got stuck in Mumbai for almost two weeks before it got released. I called to inquire about the package when it got stuck in Mumbai, and they replied that it was customary rules any imports has to be in hold for few days. I told them it took almost two weeks now and UPS was supposed to be have delivered it in three to five days maximum. Finally, after much awaiting, the package started to move toward the destinations. When the package arrived at my relative's place, my relative still had to pay import duties for the package. So never again, would i use UPS courier package service. Instead i would go for DHL courier, if i need to send package to India because in India, DHL has lots of operation there and services is faster there.