✅ Regression testing is when testers examine software between different iterations to make sure it still functions despite changes to the code. Even minor changes may result in serious issues without these checks, potentially causing previous bugs to re-emerge. This generally requires automation due to the complex nature of retesting every component; many companies forego regression tests for this reason. Testers could conduct these checks on individual units, singular components, or the whole product – the exact tests required mainly depends upon the project and its scale.