[ps67]

I agree with @Davidfor.

I respect everyone's opinions and everyone with his Kobo and calibre does what he wants. But in my opinion the best way to use the possibility that Kobo gives us to use the collections is to create a non-exaggerated number of them, let's say 20 - 25 at most (I have 11 until now).

I also think that You can certainly create collections using tags, but I don't do it to have more control over collections. I decide in which collections a book goes, without having to handle the tags every time, because if I would choose to use them for collections without check them I would get too much confusion.

While as regards the series I would tend to the most obvious use: the series are a set of books that are part of the same story and usually must be read in a specific order and Kobo is the only reader which can handle them with calibre. So I don't use them to create collections, using the series information, even if it is rather easy, because it is a useless duplication of something that already exists.