Those tires are pretty groovy!!
Me buy used tires...never!
I've got two OCD buddies who always replace their tires at 5 years, including spares. They give me their castaways. I have a local guy who mounts them for $10.
Given all the trailers and other equipment and vehicles, I have over 80 air holding tires on the ground. Something is always going flat...nice to have tires saved up to resolve the problem . For obvious thorns/nails, I use tire plugs while still mounted on the vehicle. I found a source of extra rims on CL for free...so have a bunch of spare tires for all the various needs.