I'm a fourth year at NYU so what I say may have changed a lot.
I vaguely remember first year - classes were from 8-5 everyday.
Friday may have gotten out at 2, but I can't quite remember.
Twice a week there was lab and it would sometimes end at 5:30.
Second year is when you have evening labs and get out at 8:30pm once or twice a week.
I'm sure there are many first year NYU students on this site that can answer your question better than me. 😛
Overall, first year hours aren't too bad. You have plenty of time to study. You'll find that after a month, less and less of the class actually attends lectures (because they are transcribed) and you'll have more and more free time!