The 25 year old home that we recently moved into has ClosetMaid shelving in all the closets. I don't know for sure when they were installed, but I assume when the home was built. The shelving and support brackets are made of steel but the old brackets have plastic connectors between the front of the bracket and the shelf. These plastic connectors have gotten brittle over time and are breaking and we have been experiencing occasional shelving crashes when the plastic connector eventually breaks.  Fortunately, these brackets have been redesigned so that they don't require the plastic connectors. So, when an old connector breaks, you have to throw away the old connector and the old metal bracket and replace it with this new bracket. I have decided to purchase these brackets in bulk for a good price on Amazon, instead of paying twice as much when you buy a package of two at a big box store. I guarantee that you will eventually have to replace most of your old brackets. In order to prevent future catastrophic crashes, I plan to start replacing every other bracket which should make the installation stronger and safer.  I will do this first in the closets which have heaviest clothing - i.e. suits, coats, jackets and also where heavy items are stored on the shelf.