How Often Should a Mechanical Clock Be Serviced?

The short answer

A mechanical clock that runs daily should be cleaned and oiled every three to five years and fully overhauled every eight to twelve. Clocks that sit unused are not exempt — oil thickens whether the clock runs or not, and a clock that has sat for twenty years needs an overhaul before it is run at all.

Why the interval matters

Clock oil is a load-carrying film only a few microns thick. As it oxidises it becomes sticky, then abrasive as it collects brass dust. A pivot running in that paste wears an oval hole into the plate, and once the hole is oval the wheel is out of depth and the clock loses power. Bushing that hole is straightforward work; letting it go until the plate itself is damaged is not.

A realistic schedule

Annual: check rate, level and beat, and look for oil that has gone dark. Every three to five years: professional cleaning and oiling. Every eight to twelve years: full disassembly overhaul. After any move: beat and level check, always.

Signs you should not wait

Winding takes noticeably more effort. The tick sounds uneven. The clock needs winding sooner than it used to. The strike is weak or the chime drags. Any of these mean the movement is losing power somewhere, and running it in that state accelerates wear.