The airlines view your luggage differently. They believe baggage is meant to protect the contents and that scratches, dirt and damage to protruding straps and wheels are part of normal wear and tear. What that means is the airlines won't be liable for things like that happening to your bags, though more dramatic damage may be deemed worthy of repairs or replacement at depreciated value. They also won't be responsible for whatever may happen to oversized or over-packed bags. International travel is defined as any trip that includes an international destination on its itinerary.
Pay is on depreciated value.
The airlines will not be responsible for it. Not even if you bought excess valuation. Maybe your homeowner's policy will. Each airline sets its own rules about deadlines for filing a lost-baggage claim. Airlines also have been known to pass the buck, each claiming the other airline was at fault when a bag is lost or damaged on a multi-carrier trip.