alt Hacker NewsPracticing your retrieval is actually one of the best ways to retain knowledge of something. Flashcard programs like Anki are really great because it identifies where you need more work and drills you on your weak points -- it feels awkward working constantly on your weak points, but you get quantifiably better results with the flashcard method it uses.
Some people criticize flashcards as optimizing for rote memorization and deemphasizing understanding, but you'll never achieve understanding or mastery in general without a solid platform of knowledge to work from.
My problem with Anki is that it's very, very inefficient. It will take much more time and effort to memorize the vocabulary words you learn, and losing those words is very quick. It's much better to use SRS with actual and varied sentences.