Today, many organizations reduce homegrown software development efforts by purchasing off-the-shelf solutions instead of building them in-house. This strategy can be very cost effective if the Commercial Off-The-Shelf (COTS) solution meets specific company needs. Unfortunately, in many situations, COTS solutions disappoint. As a result, companies usually have to undertake a major COTS enhancement project that is comparable in breadth to building a custom developed solution. Thus, it is important for companies to not rely on vendor claims of high compatibility alone. Instead, organizations should conduct their own compatibility assessments. One technique, called Function Fit Analysis, is particularly useful.
Read more about the pros and cons of off-the-shelf and tailor-made solutions in this recent article by Lori Holmes: http://www.executivebrief.com/article/off-the-rack-or-tailor-made-whats-the-best-fit/.