They're cheaper to replace than most tow bills. I think I paid $110ish for both. They're near impossible to diagnose without a Scope, so checking it in a parking lot is very unlikely. Finding a good sensor in the middle of nowhere isn't my idea of entertainment. Then there's trying to find a shop that can competently diagnose it and the down time impact on the travel schedule etc. Took like 60sec to swap both since all the work was already done.Alright..............so if they fail so frequently and randomly after a few 10's of thousands of miles you might as well and just wait until they fail. I am at 15 years old and over 510,000 miles with zero issues with either sensor. Personally I have not seen that many fail to worry about it to this extent but to each their own.
So I mention it so they can make their own determination. After my own experiences I'd rather do it when convenient. But if you disagree...that's your choice and freedom