Clock fit ups allow a clockmaker to build attractive, high quality wrist watches without the time and also bother of starting from scratch with individual components. Clock fit ups (clock inserts) are preassembled devices that one locations in a hole pierced via the case. This approach is specifically appealing when the focus of the undertaking gets on creating and creating the frame instead of on assembling parts.
Clock fit ups do have some downsides that could restrict their allure. All components (hands, dials, lenses, bezels) are preselected, constraining design alternatives. If you don't such as any of the readily available combinations, you're out of luck.
But also for some clockmakers enough is gained to compensate for having to give up freedom of option. Saving time, as currently mentioned, can be a big gain. An additional is when a musician wishes to convert a sophisticated showpiece into a wrist watch.