Don't waste your time and money with those. Though yes it's made from kevlar, it's not even a good quality kevlar. It's cheap crap, Anon.
If you want something for your sleeves, look at the steel versions.
>Also wondering if there are any sleeves with NIJIII ratings against bullets since vests only cover torso.
Not possible, I'm afraid. It'd have to be hard enough to stop a Level 3 round and that means no flexibility. Look at medieval armor for example, think of it like that.
>I've also read that material in bulletproof vests break down after two years
Not exactly. It's more of the epoxy/glue/binder that starts to deteriorate over time. But yes, it would still need to be changed out when it recommends (though you could get away with a bit more).
And as >>4495
said, the more you wear the more weight that is for you to carry. I got an adjustable weighted vest along with some ankle/arm weights and wore it all any time I wasn't at work. The more I got used ti the weight the more I added on. Really good idea there for you.
Stay safe, Anon.