Variability, Not Repetition, Is the Key to Mastery

I've come to believe that consistently engaging with ideas and concepts through a variety of media "naturally" embeds them in memory and understanding. I feel coming across information from different angles and in changing contexts provides a form of implicit repetition that for me makes explicit systems (like SRS) unnecessary. What seems crucial to me is having sufficient variability but also making sure it is introduced within an appropriate timeframe.