Every so often you're right... you certainly should consider the costs of automating the test versus the risk of regressing. But note that once you you have a

Every so often you're right... you certainly should consider the costs of automating the test versus the risk of regressing. But note that once you you have an organization good at writing tests, the incremental cost of writing a test is very, very small. We like the term "10x" around here. Design systems for 10x the customers of today. Write code that will survive for a year. (Otherwise it may have been wasted.) Only fix bugs once so you can grow the engineering team without rehashing old issues.