Nothing is more headache-inducing than when an airline loses track of your checked bag and you arrive at your destination — and your belongings do not.

But travel experts say lost or delayed luggage can actually present an opportunity — to go shopping on the airline's dime. 

"When your bag does get delayed, you are essentially allowed to go purchase things that you need in the interim," said Scott Keyes, founder of Going.com, a travel tips site. 

Of the 362.6 million bags checked on direct flights with the 10 largest airlines and their partners from January through September, 2.25 million were lost or damaged, according to a report from the Office of Aviation Consumer Protection. 

The rate of mishandling bags was even worse this year: Airlines lost or damaged 93,275 more bags from January through September of 2023 compared with the same period one year earlier, according to the same report. 

The sliver lining is that Federal regulations actually require airlines to compensate passengers for expenses they incur when their bags don't get from point A to point B as promised in airlines' contracts of carriage. 

Specifically, under Department of Transportation regulations, if a bag is delayed, airlines are required to reimburse customers for "reasonable, verifiable and actual incidental expenses," and cannot set limits on daily expenditures — such as $50 — for each day that a bag is delayed. 

Rolexes probably not covered

That's the upside to an airline temporarily misplacing your bag: You can essentially go shopping for free. 

"You're not going to buy a Rolex, many people wouldn't consider that reasonable. But if you need a new set of clothes and a new hairbrush, those are things that absolutely should be reimbursed by airlines," Keyes said. "I wouldn't personally be spending thousands and thousands because the airline might fight you or say they weren't reasonable expenses — but you don't need to scrimp and save and only shop at the dollar store."

Reasonable expenses can include the cost of lost or delayed clothing, toiletries and more. 

"At first blush, when your bag doesn't show up and is delayed, it seems like a headache, then you take a step back and say this is actually an opportunity," Keyes said. 

It's similar to when an airline after canceling a leg of your trip, rebooks you at no additional cost on a more favorable flight that would have otherwise cost more money. 

When is a bag considered lost?

The exact number varies from airline to airline, but most give themselves between five and 14 days to try to track down a given piece of luggage before declaring it lost, at which point passengers are entitled to reimbursement for lost items.

Under DOT regulations, passengers on domestic flights are entitled to claim up to $3,800 depending on the total combined value of the items they were traveling with. 

Airlines will typically ask for an accounting of items, particularly valuables, contained in lost bags, or proof of contents through photographs or receipts. 

"You won't automatically get $3,800, but if you have stuff in there that adds up to that amount, you would recover that," LegalShield attorney Ben Farrow told CBS MoneyWatch. "If you packed fancy tuxedos and a ball gown, things of value you could demonstrate were in there, they would pay up to $3,800."

On international flights, despite most passengers packing more items when traveling abroad, the maximum reimbursement limit is roughly $1,700, under a treaty called the Montreal Convention.

Wheelchairs, walkers, prosthetic limbs

An exception to the limit applies for passengers traveling with prosthetic limbs or assistive devices such as walkers and wheelchairs. 

If an airline loses a passenger's assistive device on a domestic flight, the company is liable for the full cost of the device, even when it exceeds $3,800.

International flights are less clear. Lost assistive devices in flights abroad are "subject to the maximum liability limit set by the applicable international treaty," according to the DOT.

How to get reimbursed

When the conveyor belt at the baggage claim stops turning and your bag has not appeared, immediately file a lost bag claim ticket with the airline. 

Know your rights, outlined above, and if an airline tries to give you a $50 voucher, reject it. 

Generally speaking, the more information and documentation you can provide the airline, the better your chances of being fully reimbursed will be. 

"Especially if you are talking about electronics or equipment, having the model numbers, serial numbers and photographs is all the better," Teresa Murray, consumer advocate at U.S. PIRG told CBS MoneyWatch. "They won't expect receipts for things you bought five years ago, but you would need to have some kind of itemization."

Delta

File a form to report your bags, delayed, damaged or lost with the airline here. 

To receive reimbursement for expenses incurred related to delayed bags from Delta, save your receipts for interim costs and submit them via the airline's "Out of Pocket Expense" form. Receipts are required for reimbursement, the airline notes on its site.

Delta states on its website that "reasonable expenses are generally determined as $50" per day, though it acknowledges that's not a cap it can enforce. 

United

Report your bag missing or delayed at the airport's United Baggage Service desk or online using your bag's checked luggage tag number.

The airline states on its site that "if your bag gets delayed, we will pay you back for any surprise costs if you send us receipts."

Submit receipts for interim costs while your bag is missing here. Claims are typically processed within four to six weeks, the airline notes.

Passengers can submit claims for permanently lost bags after five days here by describing the bag, listing what's inside and submitting proof of its contents, if possible. 

American

The airline advises passengers to report their bags missing within four hours of arrival at a destination. Report missing luggage to the airline's baggage service office before leaving the airport, and use the identification number they give you to file claims online for reimbursement. 

Southwest

First, file a report in person at the airport or online. Do so within four hours of your arrival. Submit receipts for reimbursement via the same portal. After five days, submit a claim for compensation for lost bags. 

Rules of thumb

To prepare for a scenario in which an airline misplaces or permanently loses your bag, follow these tips from travel and consumer rights experts. 

• Always take a quick photo of your bag's exterior as well as its contents before zipping it closed and checking it with the airline. 
• Book a nonstop flight for simpler baggage check logistics.
• Pay for your ticket and checked bag with a credit card; card companies often offer protections for clients on top of airlines' guarantees..
• Keep medications and other valuables in your carry-on bag.
• Use an AirTag or similar tracking device to keep tabs on your bag's whereabouts .

Megan Cerullo

Megan Cerullo is a New York-based reporter for CBS MoneyWatch covering small business, workplace, health care, consumer spending and personal finance topics. She regularly appears on CBS News streaming to discuss her reporting.