In olden times you had a car ignition key and perhaps another key for the trunk. If you lost a key, you took the spare to the hardware store and for $1.50 they made you a new key and you were back in business. These days things are not nearly as simple.
We have two new-ish cars which do not start with keys at all. Each came with a set of two fobs, which need to be near the car for it to start. You can keep them in your pocket or purse and never need to take them out at all. This tripped up a friend of ours who set her purse down on the floor of her garage while she took out the garbage can. Then she started the car, drove to the grocery store, turned it off and realized that she had left her purse at home. Someone had to come bring the fob to her before she could leave again.
You can lock and unlock our cars simply by touching the car door handle as long as the fob is nearby. But both our cars operate slightly differently from each other. When you turn the Lexus hybrid off, it is totally off; you do not need to put it in park. The Jeep which we tow behind the motor home, needs to be turned off after you put it in park. A handful of times, Ken has put it in park and left the car running. Once we came out to the restaurant parking lot after having a nice dinner and saw a car running with its headlights on. We stopped laughing at someone else's stupidity when we realized that the car was ours. The headlights had come on after the sun set. I could give Ken a hard time about forgetting to turn off the car, but I was there and should have noticed myself.
Somewhere between the pickle ball court and the motor home, Ken lost his Jeep fob in the campground. We tore the motor home apart looking for it. This is a small space and there are only so many places a fob could have gone. Maybe it fell out of his pocket along the way. Campers are nice people and surely someone found it and turned it into lost and found. We checked repeatedly - no dice.
We found websites that replace fobs and reprogram them. But from what we read, it looked kind of iffy, which is as it should be, I guess. You don't want just anyone to come along with a reprogrammed fob and drive away your car. So we spent a pleasant hour at the local Jeep dealer, getting a new fob and getting it programmed and my old fob and the car reprogrammed. If we do ever find the lost fob, it will have to be reprogrammed as well. Total cost of this half hour of work - $270. Ouch!