Automated integration tests often fall by the wayside in a rush to adapt to the changing requirements.
Similar to performance and security, automated tests are much easier and more helpful if done as you go.
In the short term, this is excusable. However, over time, having to backfill tests is very time-consuming.
Further down the line, not having automated tests at all makes your life much more difficult.
Regression testing and unintended side-effects are much more frequent if you don’t have automated tests.
For Supplybunny, I messed up the automated tests in the beginning. Then I had to catch up on coverage over several tedious weeks.
In the meantime, I had to do a lot more manual testing, and worse, I had to ask others for help.
While I’m not a big fan of test-driven development, one of its advantages is that it forces you to have coverage in the first place.