Not true
I don't like to waste money.
Trying to help you not waste yours.
Trying to point out better ways of diagnosing issues.
Buy quality parts that way you don't buy twice.
In a situation like yours three sensors are throwing codes and the other has 75 thousand miles on it. Buy all four and order once if you getting them on line. Or go to the parts store once to purchase them locally. Saves on shipping or gas which ever way your purchasing them.
It also gives you a solid foundation to start diagnostics of your O2senor codes from.
If you purchase something like a scanner be it a durametric or a foxwell or an oscilliscope like a Pico. Or even just a multi meter learn to use it to it's full potential.To do other wise is wasting money time, and effort in your diagnostic process.
If your into what makes things tick learn the best diagnostic procedure you can.
Then keep improving on that procedure the rest of your life.
Those are just a few of the things I try to do