replace CSC early or let it fail one day?

ZeeBabar

Unfortunately mine went when I was about 120 miles from home in a heavy traffic jam at 5:00 p.m. In a large city. Worse, I was in the middle of 3 lanes at a traffic light. Blight changed and I could not shift to move. Had to get out of car, give apologetic smiles to folks behind me while others were making nasty comments as they passed me by. A couple of pedestrians walked over and helped push my car to the sidewalk.

Called triple A, waited about an hour feeling stupid as lots of pedestrians circled around the car staring at me. When the tow truck came, still more traffic problems, the car was loaded and then it was a two hour drive in the cab of a tow truck listening to a red neck driver telling me that in his 40+ years of owning cars, he had never had one that needed towing at 18k miles.
So, if I had known, for mental peace, I would have changed it ahead of time. However, if you are not straying far from home, maybe you can wait it out. Mine did show slight signs of it going before it went completely out. I was having difficulty shifting but thought I could get home and get it checked out.