Don't Miss Out on These 37 Credit and Debit Card Perks

On top of the cash-back or travel rewards programs most people know about, some credit and debit cards offer lesser-known -- but potentially very valuable -- perks. The specifics can vary from one issuer to the next, or even between cards from the same issuer, so be sure to read the fine print.

Related: 13 Cases Where a Credit Card Beats Cash

By law, credit card issuers can't hold cardholders liable for more than $50 in charges if a card is lost, stolen, or used fraudulently. But many issuers offer zero-liability protection, so cardholders are off the hook for unauthorized charges if they report a problem promptly.

Shoppers can double the length of a manufacturer's or store's warranty by paying with a credit card. Often there's a limit of one additional year, and the extension applies only when the original warranty is for less than three or five years, depending on the card.

Having trouble returning an unwanted purchase? Some credit cards offer a refund even if the original seller won't take the item back. Returns must be requested within several months of the purchase date, and there may be a limit on the value of the item.

When an item's price drops within 60 to 90 days of purchase, holders of some cards may be able to ask for a refund. There may be a limit on the claim amount and how much can be claimed each year.

Buy something with the right card and you may be able to get a replacement, reimbursement, or free repair if it gets damaged or stolen. Coverage may apply only to purchases under a certain amount, though, and for only several months after the purchase.

Rather than pay for insurance on a phone, pay the monthly phone bill with the right bank or credit union card and coverage is free.

Some card issuers and banks offer customers free access to credit scores. The type of score varies depending on the company, but often cardholders get a FICO score that's updated monthly.

Many cards offer free secondary insurance for a rental car when used for the entire purchase and the agency's relevant coverage is declined. The coverage isn't exhaustive -- often it covers only damage or theft to the vehicle, and only for rentals of 15 days or less.

A few cards (often with high annual fees) offer primary rental car theft and damage coverage when used to pay for the rental. Just decline the rental agency's collision or damage waiver to be eligible.

Some American Express cards offer up to 42 days of premium car rental insurance coverage for a flat rate ($12.25 to $24.95). That includes primary coverage for damage or theft of the vehicle and secondary coverage for medical and personal property -- but liability coverage is not included.

Complimentary roadside assistance can help a stranded driver get a tow, jump, refuel, or tire change. The services aren't free, but prices are set or pre-negotiated.

Travelers who've dealt with lost luggage know it's a hassle. Some cards offer a reimbursement for either the current value or the replacement cost of belongings that are lost, damaged, stolen, or sent to the wrong destination during travel bought with the card.

Accidental death or dismemberment may be covered for flights bought with a card. The payout may go to someone who loses a limb or sight, or to the family of the deceased.

Cardholders and their families may get reimbursed for otherwise non-refundable travel costs, including tickets or change fees, if a trip has to be changed, interrupted, or canceled because of weather, sickness, injury, or death.

Related: 25 Ways to Take the Hassle Out of Booking Holiday Travel

Some cards offer medical services or transportation to injured or ill cardholders traveling abroad.

Visa, American Express, and MasterCard offer exclusive discounts, such as $25 back after spending $50 at a specific retailer. Cardholders may need to select an offer and "add" it to the card before making a purchase, or make the purchase through a card issuer's website.

While many credit cards offer cash back, some also have online shopping portals that award additional cash back. Through a site such as Discover Deals, cardholders can shop at hundreds of stores, including the likes of Apple and Walmart, and earn 5 percent or more depending on the retailer.

Some co-branded airline credit cards offer free access to airport lounges. A few premium cards -- the ones with big annual fees, such as American Express Platinum -- offer access even to non-airline lounge areas at airports around the world.

Related: 11 Cheap Ways to Make Time Fly at the Airport

Some cards offer an $85 to $100 credit when used to pay for Global Entry or TSA PreCheck, which get travelers through airport security faster. Typically only one credit is allowed every five years -- but that's how long membership in the programs lasts.

Some cards (including those co-branded with hotels, of course) offer free room upgrade status through frequent-traveler programs. Spending a certain amount in a year can bring more perks.

A few co-branded cards award upgraded frequent-flyer status to cardholders who spend a certain amount in a year. For example, the offers TrueBlue Mosaic status for spending at least $50,000.

Co-branded airline or hotel credit cards let cardholders earn rewards and sometimes bonus points, depending on the merchant.

Buying flights with the right co-branded airline card brings a free checked bag and early boarding privileges.

Airline credit cards sometimes come with discounts on in-flight purchases, including food, beverages, and entertainment.

A few airline credit cards offer annual companion passes -- a second ticket on the same flight for a discount or maybe just the cost of fees, depending on the card.

Co-branded hotel credit cards (likely with annual fees) may offer a certificate for a free night's stay each year, for all cardholders or as a reward for spending a certain amount. A few also offer free nights as a sign-up bonus.

Several premium travel cards offer hundreds of dollars in travel statement credits to offset purchases at eligible partners.

The American Express Platinum card comes with free access to Wi-Fi for up to four devices via the Boingo network, which has more than 1 million Wi-Fi hotspots around the world.

Book accommodations through a card's luxury travel portal and get free benefits such as Wi-Fi, breakfast, room upgrades, early check-in, late checkout, and hotel or cruise credits.

Related: Don't Touch the Minibar! How to Avoid 10 Annoying Hotel Fees

MasterCard's Fuel Rewards program lets members earn rewards when shopping and redeem them when gassing up at a Shell station. There's a 3-cents-a-gallon discount even without accumulating rewards.

Need help with travel arrangements, or booking a last-minute dinner reservations? Try the 800 number on the back of a credit card. Many issuers offer a free concierge, although the level of service may vary.

Some card networks and issuers make arrangements to sell exclusive or early access passes to concerts, sporting events, movies, and other events.

Rather than having to cancel a lost card -- which might not be permanently lost -- and wait for a new one, Discover and Capital One cardholders can lock or unlock their cards temporarily. Many banks and credit unions offer the same option.

Customers using some cards can create temporary card numbers for shopping online without putting real account information at risk.

Related: 10 Signs You're Getting Scammed While Shopping Online

Banks and card issuers sometimes offer financial management software to help users track their spending.

Many cards charge an extra 2.5 percent to 3 percent for purchases that aren't made in U.S. dollars. Travelers can find cards with no foreign transaction fees from issuers such as Capital One and Discover.

The fine print on many cards reveals fees on balance transfers, even on promotional zero-interest balance-transfer offers. One that doesn't: the Chase Slate card. It waives the fee for balance transfers made within 60 days of opening an account.