-Too busy w/ classes, study, all the other things one does in college, etc...
-roommates that will destroy anything of yours
-restrictions on power tools and chemicals (paints, etc).
I didn't do any modeling when I was living in the dorms my freshman/sophomore years....once I moved into my own apartment for my junior/senior years I did a little modeling, but mostly was too busy to do much. I did a bit more in grad school, but also had way too many other distractions then....