2013 Itasca Ellipse on our second replacement of the transfer switch. The first one had melted wires on the output from the main relay and this second one had melted wires from the AC input. It mean...
If you're switching gen/shore with heavy loads like A/C etc the life will be shorter. I always turn everything off first to minimize electrical transients and relay arcing.
Yes unlike a house your RV vibrates and bounces down the road so ALL connections should be checked every year or two. Not just the ATS but CB panel and any other locations.