Compare Two Ways to Learn the London Underground Map by Heart

Everyone tells you to just learn the tube map, nobody tells you there are genuinely different ways to do it and one suits your commute better than the other. This compares two proper methods, weighs the weak points of each, and tells you which one to pick if you cannot decide.

You are helping a new London commuter who wants to actually know the Underground map, not just glance at it every time. Compare two learning methods: memorising it line by line in geographical order, versus memorising it by interchange stations first and filling in the branches after. For each method, give the rough time to get useful, not perfect, recall, the biggest weakness of that method, and which type of commuter it suits better, someone who travels the same few lines daily versus someone who needs the whole network. End with a one line recommendation for a beginner with no strong preference.