I have a 2014 Ford Taurus V6 (so 4x sensors). The upstream are air/fuel ratio sensors, the downstream are O2 sensors. With ~95miles on the vehicle, I'm going to change the spark plugs soon. While I had the intake plenum off, and considering the mileage, I was considering changing the sensors also. The vehicle seems to run fine.
So is it a good idea to change them now or wait until they fail? From what I can tell, O2's are generally good up to 100k, and AFR's are good up to 150k.

 

 

My Grandad used to say: "If it ain't broke, don't fix it."

In other words, if everything is good, do not mess with it. I follow what he said.

 

My Godfather(1927-1976) worked for: Found On Road Dead, and was injured/incapacitated on the assembly line. Shorty after, he made his way to the attached garage(when no one was home), he closed secured the garage door & entry door, sat on the drivers seat and started his Fix Or Repair Daily & expired. I NEVER purchased a FORD, and I'm still alive today.