I've been using Anki since 2013 (almost 5 years). One really nice thing about Anki is that it has analytics. I currently have 4532 cards and my numbers are 99.18% correct answers for "Learning" (very young) cards, 98.44% for Young cards and 92.52% for Mature cards. No way I would be able to remember over 4000 pieces of information without spaced repetition. I truly believe this is the best learning "hack" there is. I've wrote about my experience here: https://www.blinkingcaret.com/2016/05/04/hack-your-brain-lea...