* The institution: Some colleges use a quarter system (terms are shorter), while others use a semester system (terms are longer). Quarter systems generally have fewer units per term.
* The student's academic standing: Full-time students typically take more units than part-time students.
* The student's major: Some majors require more units per term than others.
A full-time student in a semester system might take anywhere from 12 to 18 units, while a full-time student in a quarter system might take 10 to 15 units. Part-time students would take fewer. These are just rough estimates; you'll need to check with the specific college or university you're interested in for their definition of full-time status and typical course loads.