Defect Prevention is the most critical but most neglected component of the software quality assurance in any project. If applied at all stages of software development, it can reduce the time, cost and resources required to engineer a high quality product. Software inspection has proved to be the most effective and efficient technique enabling defect detection and prevention. Inspections carried at all phases of software life cycle have proved to be most beneficial and value added to the attributes of the software. Work is an analysis based on the data collected for three different projects from a leading product based company. The purpose of the paper is to show that 55% to 65% of total number of defects occurs at design phase. Position of this paper also emphasizes the importance of inspections at all phases of the product development life cycle in order to achieve the minimal post deployment defects.