An elevator is designed with thousands of parts and components.. Through motions, almost every parts are in constant contact with each other. Every contacts have a direct relation with various types of maintenance. Highly efficient maintenance could reduce unnecessary moving part's wear and tear, ensure a smooth ride and sustain an expected life span.
Elevator maintenance is not just lubricating or adjustment, but constant inspection and testing. This is to ensure all critical parts been replace before breakdown.
Maintenance department with few elevators may multi task its staff with both management tasks and maintenance and repair tasks.
Whilst those maintenance department with many elevators may dedicated service technician who are working professionals with a specialized skill set to undertake maintenance tasks.
Generally elevator maintenance professional:

• Safe keep all keys to the elevators. Keys such as machine room access, control panel door , hall door opening, etc.
• Select the relevant staff from the maintenance department and send them for proper training from elevator manufacturer.
• Have a proper filing system and procedure to ensure all technical manuals, drawings, testing, inspection records and regulated standard operating procedures manuals are properly kept.
• Safe keep all elevators spare parts and tool sets. Safe keep all parts ordering catalogue to ensure that faulty parts could be properly ordered.
• Setup necessary operating procedures relevant to the maintenance department's management policy.
• Familiarized with all technical aspects of the elevators from the elevator installer or adjuster or tester. These knowledge could be useful when the time comes.
• Planned ahead and under a mutual agreement condition, take over the operation of the elevators, otherwise, if situation does not warrant the elevators for public usage, then they should be locked. Refer to technical manuals for clarifications to address why the elevators are not ready for public usage and make the necessary decision.