Most airlines authorize the airport staff to offer money for emergency, out-of-pocket expenses (toilet articles and some clothing) if your luggage is delayed.  The offer is normally quite low, as the airline usually hopes to have your luggage to you within hours.  These factors are considered:

1. You usually receive more if you're away from home.   The purpose of your trip is also taken into consideration.  For example, they may arrange for formal clothing or sports equipment rental for the engagement you might miss as a result of your luggage being delayed.

2. The length of the anticipated delay is important:  if you luggage is reunited with you in less than 24 hours, you're unlikely to receive more than a token reimbursement.  If it takes days, or weeks, you can probably justify more.

3. If you must buy a lot of clothes, the airline will probably pay half the cost.  If you insist on full reimbursement, the airline may ask for the items back before reimbursing you.