Interesting question.
Yes, think of a task:
how long do you need / how much time do you need
how long did it take you (did you need) / how much time did it take you (did you need)
It doesn�t really work with events such as meetings, concerts etc except in some instances.
e.g. a meeting, a lunch appointment
how long will it go for / how much (of my) time will it take = ok, if the person is very busy and is trying to fit the meeting into a busy schedule
e.g. a concert, movie, an outing
how long will it be / how much (of my) time will it take latter not ok
