Most items are covered by your household insurance. Insurance companies each have their own rules on portable things (phones, laptops, cameras, firearms) and when they are covered (at home or away from home). There is normally a price point whereby you need to specify the items. A laptop, for example, may be fully covered if it is stolen from your home, but there maybe no insurance when stolen away from your home.
There is also what the item is insured against (theft, damage, loss). Almost anything can be insured against almost any action. The higher the risk the higher the premium. You also need to work out the point at which it is no longer viable to insure the item. If the premiums are too high it would be wiser to "self-insure".