Your garage door opener seems like a modern convenience, but it's really a form of a door lock. While the opener's remote does allow you to get into your home without having to stop the car's engine, get out, unlock the door, lift it, start the car, drive in, and then close and lock the door again, it's really the gadget that stops others from gaining entry.
That means that you have to be extra careful about where you keep the remote and how you maintain the opener. With the right care, you can reduce your chances of having any problems caused by other people.
Not in the Car
Do not keep the remote in the car. Hiding it won't work; if someone gets into your car, they'll know to look around for potential gold mines like that remote. Keep the remote in your bag, if you carry one around, or in a jacket pocket. Just don't leave your jacket anywhere.
Always check that you have the remote when exiting someone else's car or a taxi. A common cause of losing these remotes is having them fall out of your pocket without you knowing.
Check with your garage door opener's manufacturer to see if it offers a keychain fob version of the remote. That helps stop the problem of the remote falling out, and you don't have to worry about carrying a bulky remote with you. All you have to do is remember to take your keys with you, and if you keep the remote fob right next to your car key on the keychain, you'll have no problem remembering to take it.
One other action you can take to improve garage door opener security is to replace yours if it's very old. The opener needs to get a code from the remote to open, and on older systems, this code was static. It didn't change. Newer systems use rolling codes, which make it harder for someone to eavesdrop on the code and swipe it.
If you do have a very old system, call a garage door company and have one of the representatives take a look at your current opener. You'll be able to find out about new models that are likely quieter and smoother-running than what you have now. If you have an up-to-date system already, the rep can help you find a keychain fob and ensure that your door security is top-notch.
Contact a garage door openers manufacturer for more information and assistance.