Oxygen sensors on '06 Sonata
 

Is it really necessary to replace the O2 sensors at 45,000 miles as stated
in the maintenance list? Don't most sensors last much longer, and isn't the
normal procedure for most vehicles to wait until they fail or get slow as
indicated by the PCM throwing a code? Well over $400 for parts that really
are not needed seems a little steep. Granted, I am nowhere near that
mileage, but what other little surprises await us?