The whole recallibrating deal can be an annoyance but it really needs to be done every few months for best accuracy. The PLX automatically does this so there is no need to manually do a calibration like almost all other wideband setups. The NGK AFX requires recalibrations also after a lot of use but it is not a big deal as I use it to transfer between cars. The sensor needs to be in free air to calibrate, NOT in the exhaust system which requires removing the sensor. You could do it in the exhaust after the car sat for a few days to clear way of eliments in the exhaust but it is not recommended as it can cause the sensor to read innacurately.
