You could replace the pre cat O2 sensors as preventative maintenance as their primary function contributes to fuel/air ratio. Post cat sensors contribute somewhat to fuel/air ratio but primarily monitor emissions. You are in the range where pre cat sensors can fail. Post cat sensors usually last over 100,000 miles.

I agree you should check for codes. If the pre cat sensors are acting up you may see other related codes, like a lean cylinder(s), rather than an O2 codes.

I am all about performance so I replace O2 sensors before there are symptoms or codes. On my wife's care I still replace them in pairs but not until there are symptoms. The first is the school of thought--that if it's not broken it soon will. The second is if it isn't broken don't fix it. Either route is a reasonable course of action as it relates to O2 sensors.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas