Manual testing is a software testing technique where testers manually execute test cases without the use of automation tools. It involves human intervention to ensure that the software meets the specified requirements and functions correctly.

Benefits of Manual Testing:

1. Cost-Effective for Small Projects: Manual testing can be more cost-effective for small-scale projects or projects with limited resources. Since it doesn't require investment in automation tools or frameworks, manual testing can be a budget-friendly option for startups or projects with tight budgets.

2. Flexibility and Adaptability: Manual testing offers flexibility in adapting to changes in the software requirements or user interface. Testers can quickly modify test cases or explore unexpected scenarios during testing without the constraints of pre-defined automation scripts.

3. Exploratory Testing: Manual testing allows testers to perform exploratory testing, where they can uncover defects or issues that may not be identified through scripted test cases. Testers can simulate real-world usage scenarios and provide valuable insights into the software's usability and user experience.

4. Early Detection of Usability Issues: Manual testing enables testers to evaluate the software's usability from an end-user perspective. Testers can identify usability issues such as confusing user interfaces, unclear instructions, or inefficient workflows, helping developers address these issues early in the development lifecycle.

Drawbacks of Manual Testing:

1. Time-Consuming and Labor-Intensive: Manual testing can be time-consuming and labor-intensive, especially for complex software systems or large-scale projects. Testers need to execute test cases manually, which can result in slower testing cycles and delays in the software release process.

2. Prone to Human Errors: Manual testing is susceptible to human errors and inconsistencies. Testers may overlook certain test scenarios, execute test cases incorrectly, or misinterpret test results, leading to missed defects or false-positive/negative results.

3. Limited Reusability and Scalability: Manual test cases are typically not reusable across different releases or iterations of the software. As the software evolves and new features are added, testers need to create and execute new test cases manually, which can be time-consuming and inefficient. Additionally, manual testing may not be scalable for projects with frequent releases or continuous integration/continuous delivery (CI/CD) pipelines.

4. Difficulties in Regression Testing: Regression testing, which involves retesting the software after code changes to ensure that existing functionality remains intact, can be challenging to perform manually. Testers may struggle to cover all regression test scenarios and may require significant effort to validate the software's stability after each code change.

Example:

Consider a web-based e-commerce application undergoing manual testing before its launch. Testers manually navigate through the application's various functionalities, such as browsing products, adding items to the cart, and completing the checkout process. They validate the accuracy of product prices, shipping calculations, and payment processing by entering test data and verifying the expected outcomes.

During manual testing, testers discover a usability issue where the checkout button is not prominently displayed on the mobile version of the website, leading to user confusion and cart abandonment. This finding prompts the development team to redesign the mobile checkout flow to improve usability and enhance the overall user experience.

In this example, manual testing helps identify a critical usability issue that may have gone unnoticed during automated testing, demonstrating the importance of human intervention in ensuring software quality. However, manual testing also highlights the potential drawbacks, such as time-consuming execution and the possibility of overlooking certain test scenarios.