The millisecond (ms) is a time unit equal to one-thousandth of a second, critical in computing, telecommunications, and scientific experiments where precise timing matters. Network latency, camera shutter speeds, and reaction time measurements all operate on the millisecond scale. One millisecond equals exactly 0.001 seconds, and the human eye can barely perceive changes faster than about 10 milliseconds.

The year (yr) is a time unit equal to approximately 365.25 days or 31,557,600 seconds, representing one full orbit of the Earth around the Sun. It is the primary unit for age, financial reporting, interest rates, and long-term contracts, with the quarter-day surplus handled by leap years. One year equals roughly 52.18 weeks or about 8,766 hours.