Recommended Service Interval

Been a happy Vector 3 user since late December 2017 / January 2018. A little drop of baby oil and using the Varta branded LR44 that came with pedals and so far (knock on wood) everything runs smooth. I was wondering whether there is a recommended service interval, as in ship the pedals back to Garmin and let them have a look. Or is this completely unnecessary unless e.g. the pedal body is worn out?