Majorly, why it's important to know your body scale, is because it affects sizes of prints and accessories, fabrics weight and textures suitable for one or another body scale.
Maybe you already noticed before that some patterns and prints suit you better than other. For example, large patterns look on you better, while small prints make you look bigger? Or maybe clothing with small knits suit you will but large knits make you feel lost inside the clothing? These all is about body scale and needs to be considered.
Let's look at parameters determining body scale more closely:
Three types of bone scale can be differentiated: fine/small bones, average bone scale, big bones.
To determine your bone scale, measure your wrist around. If it's less than 14 cm, your have fine bones. If it's 14-16cm, you have average bone scale. If wrist measurement is above 16 cm, you have big/grand bones.
If your height is less than 1.6m, you are petite. If between 1.6-1.65m, your height is average. Height above 1.65m is grand body scale.
Style recommendations depends on combination of these two parameters.
For grand bones and grand body scale, best patterns recommended for you are largely sized, your best fabrics are heavy weightened. Or you can choose light fabrics and wear them layered.
If you are tall (grand body scale), but have fine or average bones, you need to find balance. Too large designs on your top may look unbalanced, while small designs can make you look unproportionally tall. Try medium size patterns on your top for more balanced look.
Petite ladies with fine bones should not wear large designs, prints, patterns, knits. It will be overwhelming and will make you look lost inside the clothing. All the designs have to be chosen in proportion with your petite scale. Tiny designs are made just for you.
The same advise applicable to hairstyles. Avoid large volumized hairstyles and make then neat instead.
Petite women with average to grand bones should wear larger accessories and heavier textures. Avoid any tiny designs as they will make you look unproportional.
It's recommended for petite ladies, regardless of bone structure, to wear monochrome outfits. Monochrome styles have body elongating visual effect, which makes you look taller.
Average body scale figures usually don't have much difficulties with print sizes. Medium sized designs are generally recommended, but you can experiment with other sizes to see how well they are for you.
If you are still not sure what prints, patterns and textures are good for you, just keep on trying. Try different options in the store, compare them and you will see what is the best for your body scale.