Hair extensions can be a great option to add thickness and volume to your natural hair.If you only need a little bit of thickness and your desired extension length matches your own hair length, then standard thickness hair extensions should work well for you. They will blend in nicely and give you the desired result. However, if you want to achieve longer hair in addition to thickness, you will likely need to get two sets of "standard thickness" hair extensions. This is because the standard thickness of hair extensions is designed to match the density of natural hair. If you add longer extensions without increasing the number of wefts or pieces, it may result in an uneven and unnatural look. By getting two sets of hair extensions, you can ensure that the added length and thickness are distributed evenly throughout your hair, providing a seamless and natural appearance.