This might be of interest to forum members here:
Circuit Breaker Cover or Boot
circuit breaker cover.jpg
I've seen lot of photos of rusty terminals that end up resulting in poor connections with high resistance. It's easy to prevent with a coating of dielectric grease.
These covers would give an additional layer of protection plus prevent shorts if a tool falls in the wrong place etc.
There are a variety of colors available and they can be inexpensive from the right sources. I have a couple on order to try.