I think an important step beyond that is making the feedback loop tight. You can repro, great, but if it takes 1-2 hours then it’s going to be slow. Attack from

I think an important step beyond that is making the feedback loop tight. You can repro, great, but if it takes 1-2 hours then it’s going to be slow. Attack from the entrance/exit, once you know that part works, ratchet it down, tighten the loop. Eg if it’s a web request, first rule out query parsing and the final JSON rendering step. Then maybe it’s just some business logic without a web shim. Maybe it whittles down to a DB call inside of that that’s not performing as expected.