How long do steel plates last?

[sva01]

I bought The Last Stand brackets when I bought my steel targets. http://www.laststands.com/product/the-last-stand/
https://www.youtube.com/watch?v=SRxfFousfr4 shows how to set up the rebar and hang targets from it.
I have old firehose bolted to my steel so that it creates a loop and then I set up the rebar stand and slide the firehose loop onto the horizontal bars. This allows all of my steel to freely swing when impacted. I only bought the corner brackets from them and now see that they have expanded their product offerings. It's super compact and easy to throw in the truck to transport. The corner brackets do hold jacket fragments so I always wear gloves when handling...