Software has its own lifecycle before it is delivered to the customer, which is called the custom software development lifecycle. SDLC includes different phases such as requirement gathering, analysis, design, implementation and maintenance. We need to ensure that we start  testing from the first phase of the SDLC, which is why we  have implemented a software testing lifecycle to test each  phase of the SDLC. Where we start  testing as early as possible and try to find bugs in 
from day one. 
 
The main advantage of early defect detection is reduced repair costs.As we move forward in software development, the cost of fixing bugs increases because the work done for a particular area keeps  increasing and the rework incurs a specific amount  depending on the cost. depends on the stage in which we discovered it.