Q. How does “excess valuation” work when checking a bag on an airline and is it worthwhile to buy it?

A. Excess valuation is basically extra insurance that you can buy when you check in your luggage. It’s over and above any liability that the airline is required to pay if your bag and its contents are lost or damaged. On domestic U.S. flights, the airline’s standard liability is no more than $3300. By paying a relatively small fee, you can up the coverage to $5,000 on most airlines. Delta, for example charges $40 to boost coverage from $3300 to $4000 and an additional $50 for coverage from $4000 to $5000. For most people, it’s not worth buying on domestic flights. But where it’s very useful is for international flights, because airline liability is much less when traveling outside the U.S. Delta, for example, charges $10 for each $1000 of coverage up to $5000. Beware though: you’re still not covered for cash, camera equipment, commercial effects, electronics, jewelry, works of art or other valuables, and the coverage only extends to a Delta destination, the first Delta stopover, or your point of transfer to another airline. You need to buy the coverage each time you check a bag.