It is better to wear out than to rust out.
Prov. It is better to work until you die than to be idle just because you are old. Nancy: Grandma, you shouldn't work so hard. You're not young anymore, you know. Grandmother: Thanks for your concern, dear, but I plan to keep working. It's better to wear out than to rust out. Bill: You really ought to relax. I'm afraid you'll kill yourself with too much work. Nancy: So what? It's better to wear out than to rust out.
rust away
to dissolve away into rust. In a few years, this car will rust away if you don't take care of it. The bridge is rusting away, little by little.
rust belt
Fig. the industrial north of the United States. (Patterned on sun belt.) The economy in the rust belt is slowing down. The salt they put on the roads in the winter made my car all rusty. I guess that's why they call this area the rust belt.
rust out
to develop holes or weak places owing to rust. Our hot water heater rusted out and flooded the basement.