For agricultural research and laboratory settings, a high-precision meter with multi-parameter measurement (chlorophyll, nitrogen, leaf temperature, and humidity) is required, justifying a higher price point. Conversely, for routine crop monitoring and nitrogen management in the field, a portable, handheld SPAD meter with a rugged, IP65-rated waterproof design is more cost-effective. Buyers should match the device's measurement area (e.g., 2mm x 2mm or 3mm x 3mm) to the specific leaf types they intend to test.