Coach Controls Wiring Harness?

I received my Coupe-23-L in the mail today. I was excited to open it up and take a look at the future project. The very large laminated wiring diagram is very clear to read and should make the wiring process go smoother. I was surprised about one thing, though. All of the relays in the fuse/relay box are all soldered in. That means if one goes bad, that circuit is dead. So, forgive me if this is a dumb question, but what would be the average lifespan of a relay? Should I be less worried than I am?

Travis