In your opinion, what will happen to the cost of a software product in which a defect that could have been removed during the initial stage of testing is removed/fixed later?

The right-hand thumb rule for software testing is that the later the defect is removed, the more costly its removal becomes. The best phases to remove the defects are the requirements and design phases.

Defects escaping the design and requirements phases can become as much as:

• 5 times costlier to remove in the execution/development phase,
• 8 times costlier when removed during the testing phase,
• 10 times costlier to remove during the implementation/deployment phase, and
• 20 times costlier when removed during the maintenance phase of the software product.