When getting involved in a project it is extremely important to understand the scope of the project. By focussing your efforts and understanding all of the details you will be able to achieve great success. Project scope is increasingly important when going into existing installations. If you look at any major electronics manufacturer over the last 50 years you'll find that with daily innovation there has been an evolution into disposable electronics. With some product life-cycles being as short as six months, we need to be proactive about servicing the client base.
Take a look at Lutron or AMX and you will find companies that are dedicated to their legacy. Many times manufacturers like these can remanufacture equipment as old as 15 or 20 years old to help aid you in finding a solution for an existing project. This is great because it positions your company as a fair provider of product. However, you can quickly get into a slippery slope where you are looking at products and programs that are outside of your normal scope of work.
This will inevitably lead to additional time sunk into the project and what started out as the "right thing to do" has now turned into a headache for all parties involved. We encourage service of electronic systems but we also encourage you to manage the scope of the project. Take the time to investigate the state of the electronic system and develop and action plan that includes expectation management for your client.
In summary focusing on broad project concepts can help protect against cost creep and keep your service model profitable. Always analyze all of the angles so that you can develop a strong action plan that uses your in-house resources to their fullest.