Depends on the size and use case of the project. If it's only a small hobby project that myself and a few others use, writing automated tests instead of manual

Depends on the size and use case of the project. If it's only a small hobby project that myself and a few others use, writing automated tests instead of manual testing is overkill. If you have paying customers or have made an implicit promise to keep the service up and running, then automated tests make sense.