The maintenance ratio will differ depending on a number of factors affecting the building such as: age, service or use (severe or light), and where it’s located. For example, hiring a tradesperson in Tuscaloosa would cost less than hiring one in New York City. Your location will have a major impact on maintenance costs. With complicated electronic equipment, there is about a 10% cost for a service contract. That should be the upper limit of the equipment maintenance ratio. In high speed manufacturing, parts are very expensive and there can be a ratio of about 50% labor and 50% materials. In custodial business, the ratio is about 85% labor and 15% materials.