Steel bells are very durable unless you strike them aggressively in cold weather. You can maintain them with a protective coating (a good enamel paint) and grease on the joint where the yoke rotates on the bracket. Rope on the wheel or side arm will activate the ringing motion. If you have them in a tower, you need to frequently inspect the base that they are mounted on to avoid a tumble on top of the individual who is ringing it. A wooden base will rot and frequent motion will cause bolts to pull into the wood resulting in a loosening of the junction. You do not want to have any injuries. If they are mounted on steel beams, then a good lock washer on the mounting bolt should prevent loosening.
Harry Long, MD