In my map it's usually 3 out of 4 classes in a given session that are "set in stone" - and the fourth is an elective. They do that for the first two years to make sure you get the important things done in order. There are a lot of "take 1 before you take 2 before you take 3 before you take 4" kinds of progressions and if you don't get that straightened out early you can get yourself into a jam. They set things up so that you get through all the requirements early - I imagine that way if you screw something up you then have time to retake it as you go. Then all the electives get filled in at the end.
I have about 3 years of courses to take - I have about a year complete coming into the program. So I think technically I'm a sophomore, but they don't really work like that in "years". I imagine you could take 8 courses at a time, for example, and be done in 1.5 years
