To maintain effective test suites over time, it's essential to avoid false positives in tests, make them easy to understand, leverage a unique test suite across environments, and fine-tune alerts that are resilient to environment changes. This can be achieved by using reliable locators and alerts, eliminating unnecessary steps that add complexity to tests, adding descriptive test and step titles for easier troubleshooting, consolidating and reusing workflow steps to reduce points of maintenance, leveraging a unique test suite across all environments, and integrating your test suite with CI workflows. By following these best practices, teams can promote test maintainability, ensure a consistent user experience, and increase test coverage.