Cue what must look like a strange dance from a distance; a pocket-emptying, couch cushion-flipping and garbage bag-rummaging panic, usually followed by a spell spent anxiously peering through the window of your locked car desperately hoping to see your lost car keys inside. And yet hoping not to at the same time.
Best-case scenario, of course, is that they turn up exactly where you left them (Parent Logic insists that they will always be in "the last place you look", but then why would you keeping looking in more places after that?) But that's not always the case. And things take a far darker turn if you don't have a spare set. So here's what to do if you've accidentally farewelled your fob for good.
Don't panic, you've got a spare, right?
We could begin today's lecture by stressing the importance of always having a spare set of keys, and getting replacement car keys cut if you happen to lose one, but you know that already, and you know that doing it that way will save you a lot of money on your car key replacement cost. So let's cut straight to the chase: like the automotive version of Alicia Silverstone, you're keyless.
First, you need to figure out what keys you have. If you have an older car - like a Holden Commodore, Astra, Cruze or Mitsubishi Lancer - odds are you'll be using a traditional old-school key, no different to the one you use for your home or office.
If your car offers remote unlocking and push-button start, however, then it's likely your main key will be an electronic key fob with no visible metal showing. Or it's possible your car offers a mix of both electronic or proximity unlocking, but with a traditional metal key you have to insert and turn to start the car.
Traditional key
The old ways are often the best, and that's especially true of misplacing an old-school metal car key as opposed to a high-tech key fob. You're simply better off than the guy next door with his shinier new car. While modern keys are coded to pair with your car's engine and immobiliser, for older cars it's as simple as cutting new keys to match your locks and ignition. Sure, it's not as secure, but feel the savings!
You need a car key replacement expert, and an automotive locksmith will usually travel to wherever your car is stranded, and, in most cases, make you a new key on the spot, often within an hour. They do it by removing your car's door lock, and using your vehicle's lock code (which they'll find engraved on the lock, in your car's log book or by contacting the manufacturer) to match you up a new key on the spot. Easy.
"Expect to pay somewhere in the vicinity of $250 if the service is fairly uncomplicated."
If they can't find your code or your lock is damaged or worn, then things get considerably harder. So here we'll hand over to 30-year industry veteran Michael Benson of Bensons Locksmiths.
"The older the car, the harder it can be due to wear and tear on the lock, but if the lock is in good condition, we can remove the lock and then replace the key," he says.
"If we can access the lock code, we can generally do it on the spot, but if not, we need to take the lock barrel away, strip it right down and cut a key from that, and that takes time - but that's worst-case scenario."
In short, if the lock barrel of your 15-year-old Holden Barina, Honda Civic, Ford Falconor Toyota HiLux has taken a battering, or if the lock codes have disappeared over time, you're going to be leaving on foot.
Depending where you are, you can expect to pay somewhere in the vicinity of $250 if the service is fairly uncomplicated. Which is a lot more than the $5 or so it would have cost to get a spare key cut at your local shopping centre, but we promised we wouldn't harp on about that.
Electronic key
First, the bad news: this isn't going to be cheap. The technology involved in unlocking your car remotely means there's a lot more to replace if you happen to lose your super-smart electric key. Once the exclusive domain of premium car makers, the proliferation of remote-unlocking technology now means just about every modern car, from the newer Holden Commodore, to the Hyundai i30, Mazda 3 or the most expensive of BMWs, comes with an electronic key fob.
While not cheap, losing a single key is at least a fairly straightforward process. Your dealership will be able to clone your spare key, and make you up a new one without having to change anything inside the car. An auto locksmith can also do this for you, and often at a considerably cheaper rate, so it always pays to shop around.
Lose both keys, however, and one of your car's computers - the one that controls the doors and immobiliser - has to be reset or completely replaced to match a new set of keys. That's a job for a dealership, and the work involved means a lot more money.
Australian consumer advocates Choice looked at the average cost of replacing modern car keys in December 2014, and the results don't make for happy reading.
"Lose one key, get a replacement ASAP."
The group surprise-called 22 dealerships across NSW and South Australia, asking for quotes to replace a single key for 11 car brands. The quotes stretched from $267 to $800, depending on the brand, and whether your key unlocks your car at the push of a button (cheaper) or your car unlocks automatically when you get close to it (considerably more expensive). And remember, that's to create a new key using your spare as a clone.
The brand's surveyed included Mazda ($480 for a 2012 Mazda2), Subaru ($466 for a 2010 Forester), Mitsubishi ($267 for a 2013 Outlander), Nissan ($330 for a 2012 Pulsar), Ford ($501 for a 2010 Focus) and Lexus ($740 for a 2012 Lexus IS 250).
If you have lost both keys, regardless of whether it's a car remote replacement or a proximity fob, the quotes jumped from $1,800 to more than $5,000 to get a new set made. Yes, that's an ouch.
Now, we've promised not to go on about it. So we'll now quietly hand back over to Michael Benson of Bensons Locksmiths for the final word.
"Lose one key, get a replacement ASAP," he says. "It might cost you a couple of hundred dollars, but it's a hell of a lot cheaper than getting a whole new set.
"Consider it the cheapest possible form of insurance. Otherwise, things can get expensive quickly."
Failing that, just don't lose your keys. Super-gluing them to your hand is always an option.
This article originally appeared on CarsGuide.