I was told many years ago by more than one reputable FIAT mechanic that those O2 sensors last many thousands of miles longer than the preset counters give them credit for. I removed my entire counter unit ( gives you more space behind the console for whatever ) and replaced the O2 sensor idiogram in the dash with one for my fog lights. As an interesting foot note, I once owned a 1981 FIAT Strada which developed a noticeable clicking noise every time it was driven. The local dealer thought it was one of the CV joints and replaced it under warranty. It was later determined, since the clicking continued, to be an unusually loud O2 sensor counter.