What is a lab balance or scale?
Two things decide whether a balance gives you a usable number. Readability is the smallest increment it displays. Capacity is the heaviest thing it will take. A very fine balance is no use if your sample exceeds its capacity, and a high capacity scale will not resolve a small difference.
Where it sits matters as much as the specification. Draughts, vibration and an unlevel bench all move the reading on a sensitive model, which is why analytical balances come with a draft shield.