You are entitled to a 10 minute break for each 4 hours of work. If you work an 8 hour shift, you would be entitled to 2 10 minute breaks, 1 break during the first 4 hours of the shift, and a second 10 minute break during the last 4 hours of your shift.
You are also entitled to a half hour lunch -- away from the employer's premises, and not having to answer their cell phone or do any other type of work for them.
One other thing I would clarify to the previous answer. A non-exempt employee (in most cases) is entitled to one 10 minute break for every 4 hours of work OR MAJOR FRACTION THEREOF. So if you work 6 1/2 hours you are still entitled to two 10 minute rest breaks. Rest breaks are paid.
