One mistake bodybuilders make is using the scale solely to gauge progress. Yes, it is true that a scale is a measuring tool, but it is unable to distinguish between water, fat, and muscle. The best method is to track your progress through body composition. Scales are beneficial if used in conjunction with bodyfat instruments.
Remember, bodybuilding is a visual sport so photos are an excellent source to gauge progress, as well as taking precise measurements. Also, having an unbiased eye to provide you with constructive criticism will keep you on the right track. A bodyfat composition is a starting point, and if you don’t know where to begin you will just keep running around in circles.