I personally avoid looking at ‘collections of stories’ if I'm in a lazy mood, which is my usual state of being; I really don't want to sift through a half dozen stories, just to find only one that I like. I also avoid certain tags unless I'm feeling adventurous, which seldom happens.
Because of this I like to keep my stories as separate as possible, because it's something that I would appreciate as a reader. I go so far as to avoid multi-chapter fanfics if I can, saving chapters for fanfics that simply can't be told in one sitting. I do have fanfics that are sequels, but I make sure they work entirely independent of the other. That way if my reader decides they don't want to see something described or tagged in a previous fanfic, they can just skip it.
I hope I don't aggravate people by saying this, but 'story collections' in my opinion, defeat the purpose of tags and descriptions entirely. A single tag for one fanfic, could be seen as a tag for every fanfic in the collection, and you would have to read each story just to find out if that's true. Likewise if I was to read a description to get an idea of the content of the fanfics, it would be a broad description that tells me little about any of the stories in that collection. I could look in the chapters, hoping to find more information about the stories within, but it's easier just to avoid the one collection among all the other new posts.
I'm sure I sound picky about it, but that's how I do things, and I thought you might like hearing from someone who as both a reader and a writer, usually avoids 'story collections'.