Worn keys have always been a problem for car locks. You may have had a car in
the past that had a key that looked more like a wavy piece of brass then a key.
When the key wears the wafers inside the lock sit at the incorrect level. This
can cause the sticky feeling when you turn the key. It also can cause the lock
to wear and it may cause grooves to wear
inside the lock. If the lock wears it becomes less effective and can allow
incorrect keys to work in your lock.
Many modern cars use a more advanced lock and key system. They use locks that
have split wafers or side wafers. You can identify some of these locks by the
keys. They will appear to be milled
on 2 or 4 edges. Some of these keys though look like regular double sided car
keys. These keys can be more prone to wear, because the lock only has a small
contact area on the key.
This key is for a Holden Commodore. It is a 2 track key which has 1 track milled on each side.
Audi / Volkswagen VW key has the milling up the centre of the key.
Lexus / Toyota key. This is a 4 track key with the milling on the 2 inside edges, on each side.
Toyota uses this style of key in many of its latest cars. It is a double sided key. The lock uses split wafers which can easily stick if a worn key is used.
If this type of
key has very much wear the wafers can jump over the worn part of the key and
become stuck. Sometimes you might get some kind of warning such as the keys are
hard to turn, or hard to pull the key out or put it in, but sometimes there is
no warning and you may get stuck without warning.
If you see that your key is getting a bit worn then I would recommend getting
another one cut, especially if there is some hesitance in the keys insertion or
turning.