my opinion; it's worth to keep up with certain anki decks if what you're reviewing is HY for boards. i used brosencephalon's anki deck throughout year 2, and since his deck is primarily FA and Pathoma, i was keeping HY info for boards fresh. if your anki decks are what you learned in class lectures, then i might be a bit more hesitant to keep up with those since they can add a lot of trivial/extraneous details.
i was doing what you were doing, but i would find it difficult to keep up with the decks for previous blocks when i was studying for an upcoming test. the cards would add up over the course of a week, and then all of a sudden i would have too many cards to do.
some decks i kept up with for 2-3 months, others just 1 month. at the end of the day i still did really well. all i can say is to keep up with them for as long as possible--within your comfort zone. if it's only taking 30 mins/day,that's probably fine. If it starts to add up, maybe you can cut out decks that you've already been reviewing for months.
