In this paper, we present challenges associated with monitoring and maintaining a large telecom system at Ericsson that was developed with high degree of component reuse. The system constitutes of multiple services, composed of both legacy and modern systems that are constantly changing and need to be adapted to changing business needs. The paper is based on firsthand experience from architecting, developing and maintaining such a system, pointing out current challenges and potential avenues for future research that might contribute to addressing them.