"Prevention is better than cure"

"Prevention is better than cure" can be applicable to the software development in regards to defects.

Fixing defects is not a cost free activity. Defect fixing is a costly activity. If the defect is found at the later stage of the software development, the greater the cost of fixing it. Hence it is always better to prevent the defects and also to fix it at the early stage of software development.

Below shows the tentative cost of fixing a bug at the respective stage of software development.

Phase - Relative Cost to Correct
Requirments - 1
High-Level Design - 2
Low-Level Design - 5
Coding - 10
Unit Testing - 15
Integration Testing - 20
System Testing - 50
Post-Release - 100+

Hence defect prevention should be given utmost important in the software development life cycle. Defect prevention can greatly reduce the cost and time to market of the software.

"Prevention of defects is better than fixing it"