I kinda agree, but if the price is right, then it could be a SHTF type of item. Everyone needs one regardless for when the havenots come looking for them. Its either that or scrap it. Just a thought.They list them on ebay all the time. Most list used vest as with no warranty.
I really can't see buying a used vest unless I personally knew it previous owner very well. As taking chances with used body armor aint my idea of where to go cheap on.
A lot of it depends on how they were stored, how often they were worn, exposure to elements etc.i would just spend the money on a new one if you are going to be a security guard...vests ability to stop bullets degrades over time and most used ones will no longer stop what they were rated for when they were new.