On my flight to San Francisco, United ripped a wheel and housing off my luggage.  I was a little surprised when the baggage agent pointed to the counter sign (as she probably does a dozen times a day) and said "we're not responsible for normal wear and tear, which includes the loss of wheels and protruding parts. I can offer you a travel credit…" I tried to argue that this was hardly minor damage, and she said "We can argue all day, but that's the best I can do."  I took the $75 travel credit, and took the bag into Modern Leather Goods here in New York.  There, I was greeted by two much more pleasant surprises:  First, they repaired my bag while I waited.  Second, the repair was covered by Victorinox, with just a $15 co-pay.  I remembered I had a lifetime warranty, but only two luggage companies include damage inflicted by airlines for the life of the bag: Victorinox* and Briggs & Riley.  Victorinox's premium Tourbach
line even offers you a loaner bag while you bag is being repaired!  I've written before about my favorite Tutto luggage, but it does require more frequent repair and replacement if you use it as checked luggage.  For checked luggage, the warranty value is definitely worth considering, especially when major carriers consider this "minor damage."  Buy both Victorinox and Briggs & Riley at a discount with free shipping at eBags.com.
*applies to versions 3.0 and later of E-Motion® 360° and Mobilizer NXT®, version
2.0 and later of Werks Traveler™, and all versions of Architecture™. Other versions carry a basic lifetime warantee that excludes carrier dammage.