What tool is considered essential for effective time management?

A calendar is considered essential for effective time management because it allows individuals to organize their schedules, set deadlines, and plan activities in a visual format. By marking important dates, appointments, and tasks, a calendar helps users allocate their time efficiently, prioritize responsibilities, and ensure that important events are not overlooked. It serves as a constant reminder of upcoming obligations, improving overall productivity and time awareness.

While smartphones and desktop computers can also aid in time management by offering applications and tools for scheduling, they fundamentally rely on the organizational framework that a calendar provides. A television does not contribute to effective time management and can distract from tasks at hand. Thus, the calendar stands out as the foundational tool that directly supports the practice of managing one's time effectively.