Digital scales used to be something like a luxury toy and were used mainly with expensive substances, for example the scales for truffels or gold. Usually, people took spring scales (remember that from physics class?) or kitchen scales. These weren't very precise but good enough.
Digital Scales - Capacity
Digital scales are categorized according to their maximum capacity. Starting with 50g the market offers suitable scales for any needs. It is important not to overload the scale beyond its capacity since this might lead to irreparabel damages and warranty rights are lost. If you carry a digital scale that fits into a pocket be careful not to sit down on it. But there are hardcover cases available that protect the scales.
Digital Scales - Accuracy
An essential feature of quality scales is their accuracy. If you use bathroom scales or kitchen scales the tolerance range may be within grams, but if you need to weigh luxury substances the demands are certainly higher. Thus, an accuracy of 0.01g is nowadays standard for premium digital scales.
Many digital scales do not just weigh stuff but have a calculator function as well. It is very convenient to store for example the gold price per gram and then have the calculator get the total price on the basis of the weighing result.
Recalibrating a Digital Scale
Digital scales need a recalibration on a regular basis. Especially after a heavy shock this might be necessary. Fortunately this is no big deal. But you need a calibration weight that you get in the standard sizes of 50g, 100g or the rare 200g. For a rough recalibration you can also use some coins, this is often mentioned in the instructions for the scale.
Of course, the regular analog scales are still available. The two most known are the beam balance and the spring scale: