Your clock, being a precision mechanism, needs periodic maintenance to keep it running reliably and to give it long life.

Why won't my clock run for ever?

As dust gets in the mechanism, the oil becomes an abrasive paste which causes wear.

The longer the clock runs in this condition, the more repair it will need. Many American clocks have very strong mainsprings which will run the clock for years after the oil has gone bad, causing severe wear to pivots and pivot holes.

If your clock stops and you spray it with oil to make it go again, it will continue to wear badly, because it is still dirty. Shortcuts like cleaning the movement whole, even using an ultrasonic cleaner, cannot properly clean pivots, pivot holes, and mainsprings.

These techniques merely postpone the need for a proper overhaul.