for me, at almost 52, mobility is a major concern. if you have never had one on find one to try on first, add a full load out, then think about how your gonna move. my son bought an ar500 testudo gen 2 and put his full infantry load out on it. I can get it on and carry it for a short way, but no way im fighting in that thing. If i get down im not gettin up, at least quickly. I fully believe mobility is more important in survival than armor so heres what I did. ar 500 makes their freeman for like a 100 bucks. its very small and doesnt cover much. BUT, I can put mags on it and carry it around and move, offers minimal protection, and I can move in it cause the plates are alot smaller. For me it was a trade off I could do. With that said, as I get older and wt becomes more of a issue, I will trade the wt of the armor for more ammo and mobility.
as for a helmet, I dont have one and wont. if i ever need one there will be plenty laying around. but, I prefer to blend in and not fight to sticking out like someone who might have something to take and drawing attention. plus, in that situation, getting hit in the head may not be the worst thing in the world.