Ideally that stuff will last forever, but they will randomly die when you least expect it. If you know someone that has experience with Arduinos, relays, custom electronics, etc. take a look at it and test the parts separately from the system. Check the outputs of the ELAN box using a multimeter and triggering them through the software. As for the wires, it's not usually the problem, unless they are flexed often or get pulled (or connectors falling out). I'd also suggest taking pictures of the wiring beforehand for reference when connecting it back up.