The documentation is a bit blurry about this, but leeches are represented in Anki as tags, which are properties of notes. So if one card of your note is difficult, the others aren’t, once it becomes a leech, all the cards are tagged or even suspended, while only one deserves it.
I understand why - Anki does not provide a mechanism to tag cards, you can only tag notes - but the situation as it is makes the leech tag useless for me. I suggest to introduce the possibility to tag individual cards.
When this counter reaches 8, Anki tags the note as a leech and suspends the card.
Leeches - Anki Manual
Yes, the entire note will be tagged, but if you have “Suspend” turned on for Leeches, only that card should be suspended.
Counterpoint:
I think it makes sense to apply the “Leech” designation at the Note level. One of the main techniques for dealing with a leech – editing it – is an action you’re going to take on the note as a whole, not a specific card.
OK, I don’t have my Leeches suspended. I hate cards being auto-suspended, that’s just intrusive.
It’s logical to apply the “Leech” designation to the object that caused it, not to the parent object of it. When I see a Leech card, by browsing it I am immediately at a place where I can edit the fields of the note.
My main technique for dealing with a Leech is adding additional cards. This may be further subcards of the note (triggered by filling out fields of the cards e.g. to provide example sentences for this word), or further notes which somehow relate to that card, so I generate chunks of context.