We present an empirical analysis of defect arrival data in the operational phase of multiple software products. We find that the shape of the defect curves is sufficiently determined by three external and readily available release cycle attributes: the product type, the license model, and the cycle time between releases. This finding provides new insights into the driving forces affecting the specifics of defect curves and opens up new opportunities for software support organizations to reduce the cost of maintaining defect arrival models for individual products. In addition, it allows the possibility of predicting the defect arrival rate of one product from another with similar known attributes. Copyright © 2014 ACM.