How long a beam style powder scale last? When I started reloading a few years ago, I bought a used Lyman 500 scale, it looks old, so I bought another RCBS 505 scale as back up. Now seems the Lyman scale is going strong and will last for years, I wonder if I really need a backup scale. How old is your scale? what kind of life is expected. I guess the key is really the knife edge and the V slot, my Lyman looks in good shape and accurate. The V slot is plastics, I doubt replacement part will be available when I need to replace, hopefully many many years down the road.