If the grates rust.... you're not using them enough. They need to be constantly coated with meat grease!
My kettle is in such sad shape.
The things that used to hold up the ash bucket are gone and I rigged it with wire. The sweepers are shot. The charcoal grate dips about an inch.
I've used that sucker for indirect cooking so much that the porcelain got all pissed off and wanted to leave!
Look at this shit... LOOK AT IT!