In my opinion, a true Hoarder is a person with a mental issue that does not allow them to throw anything away. I've met a lot of guys with a lot of junk, or stuff, or materials that might be needed one day, to the point it looks like Hoarding, but I don't believe that's the correct word for it. They are just being practical and planning ahead.
A true Hoarder isn't able to let it go. They see value in every single thing that they have. If I cut a piece of trim, they want the scrap piece. If I demo a cabinet, they want the pieces, even if I cut them up with a saw, or destroy it with a crow bar. Same with scraps of tile, old faucets, and even lumber full of nails. There is an obsession with keeping it that goes beyond comprehension. In the last 20 years, I've met 3 people like this. All I can do is let them have the junk when I'm making the repairs on their homes. When I do this, they are content. If I put it in my garbage bucket, or the back of my truck, they are stressed out to the point of being borderline angry.