The bad news first is that nearly all Ford Focus ignition switches will fail. These switches were very poorly designed. Ford is well aware of this problem. But don't expect them to issue a recall, because this problem will not injure or kill anybody.
The good news is that if you oil the lock every 6 months or so using wd-40 or other silicone lubricant you can extend the length of time before it fails. Also if you are using a jiggle key-STOP!- because using a key that you have to jiggle to make it work will speed up the failure.
If using a jiggle key, get a code key made and use that. I explain this in my ' Car ign. lifespan post'.
The other good news is that my company can repair this ignition switch so that it won't fail again.
The cost ranges from $120.00 to $200.00, based on how worn down your key is.
When I repair the switch, it should out last the vehicle. I have been repairing these switches for over 5 years now, and have never had to repair one a second time.