Current hairstyle – if your current hair is relatively short, consider buying more packs of extensions. This will give you a stunning end result that will look natural and completely replace your current hairstyle.
Head size – although it may seem a little strange at first, head size also affects how many packs of strands you should buy. This is related to the area that the extensions will have to cover to lengthen/thicken the hair on the entire head. The larger the head size, the more strands you will need to use.
Desired end result – this also determines how many packs you will need to buy. Do you want to simply provide yourself with a full and natural-looking end result, or do you want to experiment and create a thick, long hairstyle like a movie star? Depending on your expectations, equip yourself with more packs so that you do not run out of strands to create your dream hairstyle!