How "closely" must a slip be linked to the index?
In "How to Take Smart Notes", Ahrens states that before you add a slip to your slipbox, you should:
"Make sure it can be found from the index; add an entry in the index if necessary or refer to it from a note that is connected to the index." (p. 104)
Originally, I thought it was just important that no slip gets orphaned and is connected to some thread of notes, but this statement gives me the impression that every slip must be no more than 1 degree of separation away from the Index. But once your slipbox grows a significant amount, this will cause your index to get cluttered, which runs counter to what he says later:
"[Keywords in the index] should be chosen carefully and sparsely. Luhmann would add the number of one or two (rarely more) notes next to a keyword in the index." (p. 106)
How do you interpret this for Zettelkasten? Is it crucial that there's no more than 1 degree of separation from your index? Or is it just important that it's eventually connected (e.g. with potentially 2, 5, 10, or more notes between the Index and the new slip)?