Cost estimation for a project requires good planning. You must determine deliverables, identify cost drivers, analyze efforts by resource type and inform yourself about hourly rates. You must apply a contingency level for each component. The credibility of an estimate lies in its accuracy, precision and consensus between experts and the project sponsor. It is justifiable to devote the time required to prepare quality estimates.
Software modifications are costly to develop and maintain. They represent major risk factors for an implementation project. We suggest adopting business processes supported by software packages rather than making modifications. Before modifying a software package, it is essential to understand all costs related to design, maintenance, support and migration. As a last resort, it is possible to develop an extension without compromising the integrity of the software package.