To replace or not to replace?

[dso]

I have a 2002 3.0L with only 110Km or 69K miles.

Besides your engine light going off and the codes telling you that you might need to replace your O2 sensor, is there any way that someone can tell that you need to replace a sensor?

My light came on for the first time and went to my indie shop to get a diagnosis. Guy said the I got a error code for my pre O2 sensor failing. Just wondering peoples thoughts as the engine light did go off the next day and the truck runs great and i feel no lost of power or any other issues.

I guess I'm wondering if I should just go ahead and replace it since its never been replaced before.

Its going in for a oil change anyways and was thinking of changing the spark plugs and battery since there are original items also. Yes or No?

Anything thoughts would be helpful.