Oxygen sensor - 07 Camry 4 cyl
 

Any guidance on how long these last/if or when to have tested or replace?
Thanks!

The sensor is monitored by the cars engine computer. Typically if a problem the check engine light will illuminate.

Other then the check light coming on you might be concerned if the MPG takes significant drop although the cause could be many things.

Life may be 80-100K miles. Typically the heater built into the sensor fails.