As the text for the question is limited in characters, I'm continuing in the comments :) My take would be external - Your day to day programming (may be on th

As the text for the question is limited in characters, I'm continuing in the comments :) My take would be external - Your day to day programming (may be on the job), interaction with teams, contributing to open source applications internal - Working on your basics, learning and reviewing your technical knowledge ( like brushing up on algorithms, computer architecture, etc) But I believe I'm missing something subtle here. What would your take be on that? I'm currently trying to learn machine learning from the basics (ie stats, probability, linear algebra etc) and I'm quite interested to learn better ways to sharpen my skill.