I have my machines PM serviced every three months reguardless of how much or how little use unless the hours on the guage show sooner attention being needed.

Years ago we shifted PM service down to four month intervals instead of the three month plan. Big mistake!
It wasn't long before extra attention was needed. Perhaps it was just the way things worked out? Who knows. Once we went back to the three month intervals, things seemed much better.

During regular PM service you can catch things before they become a bigger problem. There's nothing worse than a machine breaking down during use. Plus, it always seems to be during a time when things are busier than the norm.

At least that's how it's always worked for me.

Jake