My sister recently flew on Delta (award ticket), and her luggage was delayed almost 48 hours. The rep at the airport told her to buy whatever she needs and they would reimburse her. She bought 2 full outfits (even shoes and a pocketbook). A day after she filed a claim online they emailed her saying that she will receive a check in the mail to cover her expenses (just about $700).
Didn't even need to call....
The lesson I've learned from this is that if my luggage gets delayed I should immediately go out and buy a new "set" of everything (full outfit for each day toiletries etc.) at a place that accepts returns (this way in the event that I'm not covered fully I won't lose any money).