Urg, I have a friend with this issue. I find it particularly vexing because, in her situation, it's brought upon by mostly delusion, but also an unwillingness to fix an easily-remedied situation This friend and her mom have a situation that would likely be considered hoarding by most relevant professionals. With them, there is a (likely) delusional belief that a lot of their collected possessions have value. So with them, it's not hoarding junk; it's this faux high-brow activity of collecting "antiques" or curiosities. One of their relatives died leaving a house filled with old musty furniture; both my friend and her mom drove hours to the house and pillaged the place, taking home all these pieces of old wood furniture. Admittedly, many of them were/are cool. It wouldn't have been so bad, but they both live in small, modern (1990s/2000s) two-bedroom townhouses/apartments with no storage capacity. Further, while some of the furniture was cool by itself, it didn't really have a place in a more modern home. So aside from a generally cluttered and over-stuffed look, their places looked schizophrenic in the decorating. Also, most of it, antique or not, cool or not, was junk, ruined from years of neglect and wear and unsalable in most markets.
Despite both suffering from hoarding issues, my friend and her mom have two separate issues; my friend's mother has old stuff that she just wont get rid of (a lot of which is in bad shape). However, she, in her later years, doesn't really take on any new possessions. For example, she moved out of her first home and proceeded to take out the built-in, ceiling-to-floor bookshelves, and she's still carrying the stupid things around with her, decades later, from place to place. My friend, on the other hand, continues to absorb material items, but she's not necessarily opposed to getting rid of things. She used to work in retail, which of course made it significantly easier to get these things. She has several large storage bins of old makeup samples and testers she's collected over the years. Although 5-10 bins may not seem like a lot, those 5-10 bins contain A LOT of small cosmetics. Mind you, none of it would actually be sanitary to wear at this point, but she still hangs on to them because they still look new. She's also collected a lot of clothes (most of which no longer fit her) and shoes and impractical domestic items. She told me how she unpacked a box she came across from an old move and there were 10+ ice buckets in there.
To be perfectly honest, I myself carry a lot of stupid shit around with me. I have way more clothes and shoes than what I need and I do tend to heavily and redundantly accessorize my kitchen and bathroom (I've cut myself off from buying anymore bar soap until what I have is gone). And most people have at least one to a few areas in which they go overboard. What really makes me loathe my friend's situation is that her accumulation of possessions is actually causing her tangible and significant issues. What happens when you need to move and you have a lot of furniture? It needs to go with you. And if it isn't you who moves it, then it has to be someone else. Thus, my friend is constantly harassing her male friends (myself included) to move her junk for her. I actually planned a longer trip during her last move so I couldn't physically help her. She's had to get storage units to store the extra junk. Unfortunately they cost money which she doesn't have, so she defaults on them and has to either move all the stuff out or lose everything to a forced sale. It's really a sad situation, and it would be so easily resolved by just filling up her car and taking stuff to the dump. But she just will not do that.