Deciding “how much” to register for in any given term is referred to as your academic “load.” To be a full time student requires a minimum of 12 credits, but you could reach up to 18 credits and be in the full time fee range. Taking 19 or more credits in a semester is considered an “overload,” and an additional fee is charged for each hour of the overload.
Aside from the facts of academic load, each registration is a matter for the individual student. Take into consideration the combination of courses you are taking. Meet with advisors to make sure you have the key courses for sequences and courses required for admission into your major. Know GPA issues related to your major. Know yourself. Keep in mind that as you increase hours up to 18, you are decreasing the amount of time for study and other activities outside of the classroom. Try to make informed decisions. Challenge yourself to do more if you are underachieving, and strive for balance when you plan ahead.