In the context of equipment maintenance, which step is typically done once per year?

• A. Replace battery
• B. Check power cords for fraying or wear
• C. Clean exterior surfaces
• D. Recalibration

Answer: (D)

Calibration keeps the device accurate by correcting drift in readings and outputs that can occur over time. Electronic sensors and output channels can drift due to aging, temperature changes, or following service, so regular calibration verifies that what the machine measures or delivers matches known standards. Because drift tends to accumulate slowly, many equipment maintenance programs schedule this as an annual task to ensure safe, reliable performance and to meet quality requirements. Other steps like replacing a battery, checking power cords, or cleaning surfaces are routine or condition-based checks rather than a fixed annual calibration; they don’t directly guarantee measurement accuracy the way recalibration does.