High-quality scales use precision sensors that can detect changes as small as 0.1 lbs or 50g.
Wi-Fi scales are more convenient because they sync your data automatically to the cloud without needing your phone nearby. Bluetooth scales require the app to be open and the phone to be in range during the weigh-in. buy a scale to weigh myself
Always place your scale on a hard, level floor (tile or wood). Avoid carpets, as they can cause the scale to under-report your weight. High-quality scales use precision sensors that can detect