I have twice had luggage with broken wheels replaced by DL. The first time no second thought was given and the second time, the agent in the baggage service office said "generally, we don't cover wheels, but let me take a look." Upon inspection, I was given a brand new suitcase. Both times, I took the Skyway brand on hand in the baggage service office and they have been surprisingly durable. The other item that was damaged, they asked a value, I looked up how much a new one would be on my phone, and they cut me a check for the amount.
Every time I have needed to go to the baggage service office has been a very good experience and agents have been very nice and very helpful. Elite status may have an impact on the service one receives here and one of the primary reasons I have brag tags on my luggage.