How many miles do our O2 sensors last?

I'm at 70k miles, changed to the RV6 DP with defouler+ Tune about 1,000 miles ago, and got a Check Emission for 24 hours.

Wondering if it's on its way out and I should proactively change...I need to change state plates and will more than likely need a new emission test, which is why I'm stressing/asking.

 

as you know, using a defouler "tricks" the 02 sensor.

pull the code, and see what the code is for.
if the code shows that the a specific 02 sensor(bank 1 or 2, sensor 1 or 2) is running lean, you know that its the defouler, and you just need to adjust the defouler.

you'll need to get your Check engine light off to pass the inspection/registration.