Depends on the exhaust layout, and how close they get. My buddy had a Chevelle that went through starter solenoids every few months until I finally convinced him to put a heat shield on it, never had another one go bad after that
Personally, it's cheap insurance and if you've already got it on there, I'd just leave it.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.