You can see the effect with the death of an older person. Say, Widow X dies. She and her husband lived in that house for 46 years. Naturally, over that time, the attic, the basement, the back room, his shop, the garage have filled up with valuables and keepsakes and things that could be of use, once they get a little smart repair. Now, that the owners are gone, the property needs to be put in a different condition. So most, if not all, of those spaces need to cleared out and the contents sold, given away or thrown out.
There may be a similar situation with a personal library, books present but unread and passed over many times. Amazon and others maintain 'wish lists' of items such as books that seem promising but have not been purchased. I have many items on my reading wish list and far more in my Kindle library.
I have been using the Pocket service connected to the New Page/New Tab choice in the Firefox browser. I find that it is easy to add an item to the Pocket collection of web articles Pocket thinks I might like and it is difficult to find them after they stop appearing on the New Page page. So, I have accumulated 56 articles already.
With books, tools and many other kinds of lists, I wonder about several questions. Do I have too many items? Should I work with, digest, read, master, delete some items before adding more? How much is this list helping me? Do I refer to it? With any listing, it is common to ask if it is complete, with nothing that should be on it, missing. It is also common to inquire whether a list contains duplicates, is "padded", either through oversight or deliberate duplication.
With any list, I wonder how current it is? I added an item yesterday. Should that item still be there? I could drive myself nuts considering and re-considering each item each day. Still, the contents might no longer be appropriate. I listed a book that sounded good but that was a year ago. Is that book still a good choice or has it been superseded by a more recent book or a devastating attack that shows the book is worthless?
