Originally Posted by Fan4Focus
"What is the reccomended mileage interval for changing the key lock cylinder out? What is involved in doing that? Will I have to have the car re-keyed? (hope not, I have 3-4 sets of keys for it now)."
I changed mine out at about 110K due to starting to have some issues with it. It is not that difficult to do and I bought a cylinder that came with instructions how to make it work with the original key and the whole process of replacing the cylinder. Takes a little time to figure out the first time but, hey, now I am a lock smith :-) I will try to find a link to send you to where I found mine.
Here is the one I put in mine. http://www.ebay.com/itm/Ford-Focus-I...sories&vxp=mtr
I chose the one with all the plates to key it to my key. Like I said, it was not a big deal. I had to read the instuctions about installing the plates a couple of times before I got it but, if you have a little mechanical apptitude, you will figure it out.