Applications support engineers perform maintenance on existing software and help customers solve system problems. As an applications support engineer, you need to evaluate issues and decide which of them get priority, modify existing software and documentation, train employees on any changes made, and implement a plan for future improvements. To accomplish this, you may need to work nights, weekends, or holidays. Some employers ask you to identify areas where a system is lacking, establish end-to-end monitoring systems, and ensure staff gets proactive notifications of potential problems. This is a collaborative position that often works closely with engineering and sales departments.