When does “use both Claude and GPT” stop being useful advice?

A focused question about when multi-model coding workflows help and when they add overhead.

“Use both” is common advice in AI coding discussions, but it is only useful if each model has a job. For a small bug fix, one model plus tests is probably enough. For larger work, the split might be: Claude for architecture Codex/GPT for diff review Gemini for UI alternatives local model for cheap drafts Where do you draw the line between a useful role split and just creating extra coordination work?