**Regression Testing** isn’t about erasing the past—it’s about confirming that the past still holds strong.

**Regression Testing** is an essential software testing method that checks if existing functionalities remain unaffected after introducing new features, correcting bugs, or modifying code.

**Primary Goal**: To detect whether recent code changes have compromised existing features and to preserve the system’s reliability.

**Practical Example**:

Imagine you’ve integrated a new “Wishlist” feature into an e-commerce application.

During regression testing, you need to confirm:

- Is the “Add to Cart” function still operating correctly?

- Does the “Apply Coupon” feature still provide discounts as intended?

- Is the order history displaying accurately?

When adding the Wishlist feature, code alterations might unintentionally impact other components. Regression testing ensures these potential problems are caught and resolved.

**Why is Regression Testing Essential?**

1. Addressing one bug can sometimes create new, unexpected issues.

2. Introducing new features might interfere with current functionalities.

3. Code refactoring or optimization may lead to logical or operational errors.

4. It’s vital for upholding software dependability and performance.

**When Should Regression Testing Be Conducted?**

1. After implementing a new feature.

2. Following the correction of a bug.

3. After major code revisions or refactoring.

4. Prior to launching a new software version.

**Regression Testing** goes beyond simply revisiting old code—it’s about safeguarding the software’s stability, quality, and user confidence.

It’s the duty of a proficient QA engineer to ensure new additions don’t break existing features. Thus, after every update, it’s crucial to review and verify that everything still functions as it did before.