Gp's point is about how there are many things worth learning even if you can't immediately see how they will be useful, and not about urgency or timing. Sure you can pick up a book and learn about b-trees if you have to but you might not even know that a b-tree is what you need in a particular problem if you never learnt it in the first place. Most algorithmic problems in the wild don't present themselves cleanly with a signpost saying 'this is an X algorithm problem'