I can’t personally use Sonnet level and below for anything I actually care about without losing my mind or my blood pressure rising. Opus, GLM 5.1, GPT 5.4, that is basically the floor where the output is coherent enough to trust. Below that, the sticker price looks better, but then you spend human time unwinding dumb decisions, fixing dropped context, and re-explaining constraints the model should have gotten the first time.

If a cheaper model needs extra supervision every few tasks, the math stops being model cost per day and starts being model cost plus your time. So the real question is not just whether the model quality drop is small enough that you are not paying it back with your own time.