Question: how long would it take to watch all marvel movies before infinity war?
Answer: It would only take approximately 5 hours thereabout since almost all Marvel movies are about 2 and a half hours. However if you were to marathon all the Marvel movies of which the events lead up to Infinity War, you would take up to 13 hours. Avengers Assemble(Part 1) is 2 hours and 23 minutes.