How can you retain forever what you learn?
Smart Spaced Repetition will resurface notes based on how well you remember their contents. It might be tomorrow if you don't remember much or in 6 months if you could recall all of it.
Set Recall Questions for your notes & highlights
Try to answer the question about your learning to strengthen neural connections in your brain significantly. Quickly Review Decks of Notes based on tags/notebooks.
Track your memory over time
You can always see your memory state and react with Quick Actions on your Dashboard. Use Priming Effect (wallpapers from notes) to nudge yourself with valuable insights.
NeuraCache is shaping the way we think about structuring easily-accessible (cached) graph of insights in our mind.