Why should I insure my item for its replacement value?
The value that you specify to your insurer (sum insured) is the maximum they will pay out in the event of a claim. So to make sure you can replace your stuff with the same or a similar item if it's lost or stolen, you need to make sure your sum insured is equal to what it would cost to buy the same item new today.
What is the replacement value if the item is no longer sold as new?
Very often your specific item might no longer be available, especially with electronics. In that case you should look at the model closest to yours. For example, say you paid R12,000 for your iPhone 6 and it’s not manufactured anymore. You then need to insure it for the value of the next model up from yours. If this is the iPhone 7, which is being sold for R10,000, then you need to insure your iPhone 6 for R10,000. But if the latest model is the iPhone 10 and that’s valued at R15,000 then you need to insure your iPhone 6 for R15,000.