It depends. If you are taking any of your gadgets and gizmo's such as digital camera or laptop, and they aren't insured on your other policies if taken out of the house (or taken on planes etc), then you should get insurance to cover these for the trip. Things get broken in transit, things get stolen.
If you are insuring specific items, make sure you take a photo of the item before you go and also have any receipts, paperwork etc to prove ownership of the item later if you do need to make a claim.