Regression testing ensures that previously developed and tested software still works after a change. Given the repeated nature of regression testing, Automated Regression Testing is a suitable approach as it can efficiently handle repetitive test cases.

The "Record and Playback" technique involves recording user actions as they interact with the application. The recorded actions then form a script, which can be played back later. This technique is helpful for novice testers as it requires minimal scripting knowledge but is not always scalable.

The "Defect Age" metric is a measure of the time between when a defect is introduced into the system and when it's discovered and resolved. It provides insight into how quickly a team identifies and addresses defects. MTBF (Mean Time Between Failures) measures the expected time between two successive failures of a system.

Usability testing is geared towards understanding how end-users interact with the software and ensuring a positive user experience. The primary considerations involve the system's ease of use, its consistency in design and functionality, and adherence to user interface design guidelines. UAT, on the other hand, determines if the system meets user needs, while load and compatibility have different focuses.

Security testing primarily aims to identify vulnerabilities, weaknesses, and potential threats in a software application. It is crucial for protecting data from unauthorized access and breaches, ensuring the confidentiality, integrity, and availability of the system.

Automated testing involves the initial cost of writing and maintaining scripts, making it not cost-effective for one-time testing scenarios. While automation can handle large-scale projects and performance testing, it's not recommended when the requirements change often.

Automated testing offers several advantages over manual testing, but its primary benefit is the reusability of test scripts. Once created, automated tests can be run multiple times across different versions of the software, ensuring consistency and saving time, especially for regression testing scenarios.

Conversion Testing is focused on optimizing user actions to achieve specific goals, like making a purchase or signing up. In the context of an e-commerce site, a drop in sales and registrations post-redesign indicates a possible issue in the user's journey or experience, which Conversion Testing can help identify and rectify.

Stubs are used in incremental integration testing as placeholders for modules that have not yet been developed. They simulate the behavior of these missing modules and allow testing to continue in the presence of incomplete components.

Regularly updating and maintaining an automated test suite is crucial to ensure that the suite is always in sync with the current version of the application. As software evolves, test cases that were once relevant might become obsolete, and new test scenarios may arise. Maintenance ensures the suite remains effective and reflective of current needs.