I have a smaller version of this style coop; if you’re able to do caulking around the metal/wood join on the roof panels might help those last longer - the plywood of those panels was the first part of mine to fail due to slow snow melt from two winters getting in at the sides. It was actually pretty easy to make new roof panels though. Didn’t have that problem with any of the other panels, just the roof. Personally have not had issue with the nest box wood rotting in my prefabs but did have a metal tray of my oldest coop start to rust in year 5, so I just put peel and stick tile on it.
I also have a similar kennel type run for one flock; I use an 8x12 tarp on it. They last 1 year or so before needing replacement. I just treat it as a consumable item and replace when lots of holes start to form. Also if you keep a tarp on through the winter, don’t let snow build up on it - get one of those snow brooms and clean it off ASAP to minimize chances of bars bending from the weight and collapsing risk. I don’t let my chickens out into my tarped kennel until I’ve cleared the snow following a storm just to be sure.
Oh, and my chickens hated the roost bars…too narrow for standard size chickens and too sharp corners. So I made some others.
Wishing you best of luck with this coop! I was looking for a new prefab earlier this year and actually wanted this once but couldn’t get it delivered to my house for whatever reason, so I had to get a different one. It can take a lot of tweaking here and there to get prefabs predator proofed and weather hardy but they can be nice little coops.