"When you get an older boat, you don't want to use the old wiring," says Jon Schimoler, owner of Voyager Marine Electronics (www.voyagermar.com) in Essex, Massachusetts. "It's old, it's annealed, and you don't know how much water's gotten on it. So if you end up putting new equipment on, you cheapen the installation and gamble that the wiring is decent, and normally it comes back to bite you." This kind of recycling may cost an owner down the road when a warranty claim gets rejected due to reused wiring. Some installers may try to integrate old parts, such as transducers, into a new installation. Be aware: Transducers have a limited life, two to five years depending on usage, and are critical to sounder performance. The bottom line: Get a look at the service records of the boat, and bring in a trusted installer to tell you what you have and what you'll need.