I think all one needs is an insatiable curiosity about the world and everything therein. If you're extremely nosy (like me) you never stop being a student. It's when you no longer care to investigate or explore that you don't learn anything new.

I love the film 'Umrao Jahn, Courtesan of Lucknow', and in it there's a song (in Hindi) which translated means,
"I never did find what I was looking for, but in the seeking I learned much about the world." That sums me up I suppose.