1. the quality or state of being useful; the degree to which something is helpful or serves a purpose

Examples

• The usefulness of this app became clear when I started organizing my schedule.
• She questioned the usefulness of studying ancient history for her career.
• The tool’s usefulness in the kitchen made it worth the investment.
• Teachers often evaluate the usefulness of different teaching methods.
• The usefulness of the old computer had declined over the years.
• His advice proved its usefulness when I faced a similar problem.
• The usefulness of renewable energy sources is becoming more apparent.