I agree. The issue is when you don’t have the test harness or the code just isn’t testable. Then it really will “use up” your dev time for not much gain. Or at

I agree. The issue is when you don’t have the test harness or the code just isn’t testable. Then it really will “use up” your dev time for not much gain. Or at least it’s a harder sell. My “dark pattern” to sell this is to offer to refactor a small portion at a time, then read through as much code as I can on nights/weekends looking for unhandled edge cases. When I find one, that’s the part I make tests for. Wo and behold, it found bugs! Bonus points if the edge case actually causes issues in prod or loss of revenue. The manager is now convinced we need this thing, or at least thinking about giving us time to work on it.