Service life of o2/lambda sensors

[Rockatansky]

I've read various conflicting opinions online about the service life of o2 sensors.

Some folk say they should be replaced after x years/miles and some say just wait until your obd tells you - so what do you think?

My own car (Volvo V70 T5) is 12 years old and has covered 145k miles, so are it's o2 sensors on their last legs?

I'm thinking about this just now because I might have to swap my old ones into another exhaust, and it might be an appropriate time to replace them (although they seem pretty expensive )

[GreenV8S]

If it ain't broke ...

[davebem]

Some makes specify the are changed at intervals, on some japanses cars they advise to chage every 60k. Some makes such as french and german dont specify they are changed at all. As long as the car is running ok and passing its MOT/emissions test then I wouldnt worry.

[stevieturbo]

Change when they no longer function correctly.