The average visual reaction time is around 250–300 milliseconds. Under 230 ms is quick, under 200 ms is excellent, and professional gamers and sportspeople often average 150–180 ms. Note that your screen and input device add a little delay for everyone.

Age, fatigue, caffeine, distraction, and practice all play a part — as does hardware: a 60 Hz monitor and wireless mouse can add 20–40 ms compared with high-refresh equipment. For a fair comparison, always test on the same device.

To a degree. Reaction speed has a strong inherited component, but regular practice, good sleep, and physical exercise measurably sharpen it. The biggest quick win is testing while alert and free of distractions.