Cropping hair is a tricky business, requiring a lot of patience and tact. Individual cutouts are usually clipped by path, but if possible, the hair should always be clipped using an alpha mask to get the best result. When cropping with a mask, very fine hair is also retained.
However, if the difference in contrast between the object and the background is not as high as, for example, light hair on a light background, or dark hair on a dark background, the hair must usually be cut out by path, but fine hair can also be cut off . It is also often the case that you partly cut hair with the alpha channel and partly with the path to get a perfect result, but you need a lot of experience with the individual tools in Photoshop.