Being forgetful at home has minor consequences. Get locked out of the house? Grab the hidden spare key from the garage, call the landlord or make a copy of your partner's key. Can't find the key fob for the car? Dig out the spare or catch rides from friends until a replacement can be made. But when you're on the road and away from home, losing keys can be disastrous – or no problem at all, in some cases.

Lost Rental Car Keys

Misplaced the rental car key? What happens next depends on what happened when you signed the rental agreement. It's common for major rental car companies to offer a roadside assistance package for an extra fee. Renters who agree to buy that package may be able to get replacement keys at no cost, depending on the terms of the agreement. Renters who are prone to losing keys should check the fine print before signing anything. These agreements tend to have exceptions; for example, Alamo's Roadside Plus program won't cover replacement keys in some states.

Renters who don't pay for that protection in advance are out of luck when it comes to lost car keys. But no matter what add-ons you bought, call the rental company as soon as keys go missing. The company will provide specific instructions, but expect to have to pay the cost of having a tow truck take the car to the nearest rental company location as well as the cost of a replacement key. That alone may be $200 or more.

Lost Hotel Keys

Now that it's commonplace for hotels to use programmable plastic key cards, replacing a lost room key is usually quite easy. Front-desk staff are often able to replace a key card for free. The person whose name and credit card are on the reservation may have to be the one to make the request and show proof of identity. For security purposes, hotel staff shouldn't be willing to hand over room keys to anyone who claims they lost theirs.

If it's a true key that gets lost, hotel staff should have a spare one ready to hand over. Again, the person who made the reservation may have to request it. Expect to see a replacement fee added to the final bill. They vary by hotel, but fees are generally anywhere between $20 and $50.

Lost Rental House Keys

In an Airbnb or other rental house, it's up to the homeowner or rental agent to create policies about lost keys. One Airbnb host might generously provide a second key for free; another might charge $100 or more. At least when the Airbnb host is in the same house, there's someone nearby who can let you in.

What's really tricky is figuring out what to do after getting locked out of an empty house. That's why it's important to put the contact number of the owner or rental agency in your phone. Call right away to ask what to do. The owner or agent may come to the house to open it, or call a neighbor who has a spare key. If that person is unreachable, it may be necessary to check into a hotel overnight until it's possible to make contact. A reputable locksmith won't open a door or change the locks unless the person who's locked out can prove residency.