<p>I was wondering is there a limit to how many units you can complete per year?</p>
<p>At some colleges, there is a limit on how many credits you can take before you have to pay an additional charge. Other than that, few colleges limit you to the number of credits you can take. A normal quarter or semester load is considered to be 15 credits. Some students take an extra class to get to 18 semester credits or 20 quarter credits. Practically speaking, it is generally considered to be unwise to take more than these, as it is unlikely that you can do well in all those classes.</p>