1. You must not overwind the clock. Winding a clock spring all the way does not damage it! If a clock stops when it is fully wound, look for a lubrication or wear problem.
2. Mechanical clocks are very accurate. While most weight- and spring-driven mechanical clocks keep time within a minute or two a day, don’t expect split-second accuracy as you would get with a modern quartz movement. Spring-driven clocks lose power (and time) as the spring unwinds; fluctuations in temperature can cause the movements to expand and contract, affecting timekeeping.
3. Buy only American. Well, American clocks manufactured prior to WWII were not as well made as those from France, Germany, and Austria. European clocks had higher-quality movements and require fewer repairs today than clocks cheaply produced in the U.S. and Japan.
4. Just give it some WD-40. No, this lubricant is not your clock’s friend! Never spray the mechanisms with WD-40 as that will attract dust, ruin the cleaning solution used for its maintenance, and make cleaning and repairs more costly.