[sophe]

The worst kind of tech debt is test debt: the huge body of unidentified and undiscussed tests that never get considered. On an "agile" team where there are no test specialists, and the emphasis is on CI/CD with fully automated tests, those tests are confirmational: these tests verify that the code works as expected, and they have to run fast. If you have an SDET, then their work is most likely focused on tooling to improve the efficiency of the dev team, and not to exploring and learning about the applications to drive quality. This is delivering "working code" with eyes closed and fingers crossed, and this test debt hangs like the Sword of Damocles above your company's customers.

The role of test specialists is to try and make the unknown unknowns a little less unknown. If you have decided that it's finally time to hire a test specialist, then you have that huge test debt PLUS immediate pressure to focus on new features.