How many key do you have on your key ring? Only a few right? If you are like most people, you have a house key, a work key, a car key, a key to your mother's house, a safe deposit box key, a garden shed key, a garage key and a gym locker key and maybe a key to your old house that you just never got rid of. Add in those affinity cards that you leave on your key ring to scan at the check out counter or gas pump, plus a flash light, a tiny Swiss Army knife plus an emergency whistle and you key ring is getting pretty heavy.
So what? A big heavy key ring is a convenient place to keep all those important keys and accessories, it is big enough that you will not misplace it easily and it makes a good weapon to slug a mugger with. But it is a potential problem for your car's ignition switch that could leave you stuck with a car that will not start.
It is not a coincidence that most modern cars have an ignition switch (the thing you stick you key into to start your car) that appears similar to almost every other car on the road. This is because the Federal Government has mandated the design of ignition switches to help prevent auto theft, including a locking mechanism that prevents the steering wheel from turning.
But the ignition switch is more than a locking mechanism, it is also an electrical switch that allows the engine to start and continue to operate. And because it is a mass produced piece, car manufacturers tend to chintz on the bits inside the ignition switch. A heavy key ring hanging from the ignition switch will cause those bits to break.
Once the bits break you car may not start, or your car may shut off without warning as you drive down the street. The only solution is to replace the ignition switch which can be an expensive repair. The very best way to prevent your ignition switch from breaking is to use a separate key ring for your car keys. Keep all they other keys in your collection separate.