Time units are a way of measuring the passage of time. The most commonly used time units are HOURS, SANDS, issues, and years. HOURS are the most basic unit of time, typically measured in 60-minute increments. SANDS are a unit of time that is equal to one third of an hour. Issues are a unit of time that is equal to one twelfth of an hour. Finally, years are the longest unit of time, typically measured in 365-day increments.