What happens if you service a clock and let it sit without running it? What happens if the clock is not run and stored for a year, does the oil dry out? Is it better to run the clock once a month to get the oil moving? If the clock is sitting for a year should I refresh the oil before running the clock? These are all good questions. I will attempt to answer each one.
Unfortunately, most people let their clocks run until they start to show signs of needing servicing
It largely depends on where the clock is located. Environment should always be a consideration in whether to run your clock constantly, or not. Is it in a smoke and dust free environment? Can the humidity be controlled? Are there pets? Pet hair can find its way into the strangest places.
I like to check all of my clocks on a 2 year schedule. If all looks well, I may not do anything except look it over and add oil where necessary. I might repeat this for 4, even 6 years before signs of wear show up. Or, there may be signs of wear at the first check at 2 years. If wear is evident, I might note it and monitor it several months later and address the wear at that time. This approach will keep your collection in good shape with a minimum amount of work. If there are pets in the home you may want to inspect your clocks at more regular intervals. If the clock is sitting for a year without running should I refresh the oil before running the clock? Yes, but only if there is no or very little evidence of oil in the pivot holes.
However, a clock that is allowed to sit dormant for one year should be essentially as you left it. If you used a good quality oil, an oil specifically designed for clocks, it should not break down over the course of one year. A thin coat of quality oil in an unused clock will disappear over about 4 years with little or no trace of residue and that is the time that it needs re-oiling. The buildup of sludge often seen is the end result of repeated over-oilings over the course of many years.
I know collectors who run a small number of their clocks daily but some intermittently, perhaps once or twice a month or a year, enough to keep the wheels and the oil moving. I have some specialized clocks that I will run only occasionally like my Kienzle World Clock in order to lessen the wear but keep the parts moving. Why? This a very frustrating clock to service and I want to extend the service interval as long as possible.
Getting back to the home environment I should mention mention that concentrations of some indoor pollutants are often 2 to 5 times higher than typical outdoor concentrations. In environments with air born particulates, tobacco smoke and animal dander your clock should be sealed properly by making sure that access doors/panels are closed, that broken dial glass is replaced, large holes in the clock cases are sealed and clocks are away from areas of the house that produce higher amounts of dust and humidity (kitchens and bathrooms).
Unfortunately, most people let their clocks run until they start to show signs of servicing and at that point repairs can be costly if you are not doing the work yourself.
Taking good care of your timely treasure will reward you with years of service.