I agree with both you. The thing is, we don't need to appeal to a sense of balance. It's good practice to write tests for the things we change. But, in every

I agree with both you. The thing is, we don't need to appeal to a sense of balance. It's good practice to write tests for the things we change. But, in every code base under version control, we have data. We can make this empirical. Start aggressively writing tests for the hotspots.