For me it’s profilers. A lot of people keep optimizing their code without actually having hard data. Being good with a profiler has often allowed me to go in an

For me it’s profilers. A lot of people keep optimizing their code without actually having hard data. Being good with a profiler has often allowed me to go in and get significant improvements quickly because I could attack the code section that really took a long time vs the code sections where think the time is going. Also having detailed logging with time stamps helps a lot in identifying where the code spends most of its time.