Modern computer-aided design (CAD) systems have significantly contributed to product development efficiency and cycle time reduction. CAD models can undergo several iterations through the development process; the use of CAD tools allows for these models to be quickly altered during these iterations. Altering existing CAD models can also reduce product development cycle-time by allowing for variants of these designs to be created quickly. These benefits require the reuse of CAD models to be quick and intuitive. This work examines the effects of several original and altered model variables (both attributes and derived quantities) and the perception of the original model on the speed with which the models were altered. Models created and altered using the SolidWorks and Pro|Engineer CAD platforms are examined and compared. It is shown that CAD models with fewer, complex features are altered more quickly. Models deemed as properly conveying design intent are also altered more quickly. Models perceived as having an intuitive feature order have a higher percentage of features being retained, but feature retention does not significantly affect alteration time. It is also shown that in the absence of incentives, improper modeling procedures are not corrected and increase during alteration.