I disagree. I am always looking for ways to play familiar material in new ways. Doing so is a fun mental challenge and helps me grow as a player. For example I will take a familiar song and practice it in various permutations like: transposed to a different key, moved around higher/lower on the neck or to different strings, switch from 4 string to 5 string (or vice versa), try to play using open strings vs. closed fingerings, play the bass line on the piano instead of the bass, simplify the rhythm (or add complexity/variation), alter the harmony, etc.
In fact I have observed that the top achievers in any field are constantly refining the fundamentals of their technique. YMMV.