In situations like this I provide the client with an objective assessment that documents all aspects of the existing system. I then provide them with two scenarios. One is a complete system replacement (obviously my preferred option) and the other is a full system overhaul that includes re-wiring, new connections, new sockets, new/upgraded lamps, upgraded controls and replacement of fixtures on an as needed basis. Often times the cost of overhauling the old system is so close to the cost of new that the choice is obvious. The thing to remember when repairing an old or unfamiliar system is that once you have touched it, you own it. In the client's eyes; the longevity, performance and condition of the system after you have worked on it directly reflects upon you and your company.