How long do oxygen sensors last, anyway? Maybe they're old enough that it would be no great extra expense to replace them now. I've got not quite 60,000 miles.

96 GL Zetec ATX, white with pinstripe, nickname " Sam Smooth "
mods so far: CTA intake with homemade heat shield, KVR drilled front rotors & carbon pads w/ 500° fluid
planned mods: exhaust (want to keep it quiet), e-ram (awaiting installation), diablo chip
involuntary mods: compression increased after head gasket failure