About a week, but in the modern day it definitely doesn't take a month to get used to a city's public transport system. Phones now tell you all you need to know

About a week, but in the modern day it definitely doesn't take a month to get used to a city's public transport system. Phones now tell you all you need to know in most developed countries. Perhaps with the exception of particularly terrible ticketing systems such as the UK train system and, I can't remember why now as it's been a few years, but I hate the train ticketing in Germany too. But even in those cases, you still get where you're going, just with the chance that you'll get told off by a ticket inspector because your train isn't valid for the super ultra full moon off-peak ticket you booked. And London really does have some of the best in the world. There are a lot of rough edges, for sure, but nearly all rankings I can find have it around 10th best city public transportation system in the world which is pretty up there. Maybe now that they've finally fixed Bank station, it could even go up a few points ;). Zurich is probably the best I've experienced, and Stockholm, Tokyo and Singapore are also very good. Paris, Moscow, Madrid, New York City and Amsterdam are probably all roughly on par with London; better in some ways, worse in others, and which one you prefer probably depends on your individual preferences.