How long should nails be filed to achieve rounded edges?

Filing nails in one direction is particularly important for achieving rounded edges while minimizing the risk of splitting or damaging the nail. When you file in one direction, you help maintain the integrity of the nail structure. This technique aids in creating a smooth and polished edge, which is crucial for a neat appearance.

Filing back and forth, as suggested in some other options, can create friction and lead to micro-tears on the nail surface, making them more susceptible to breakage. Filing in a swift, circular motion or only from the center to the edges can also lead to unevenness and potentially result in jagged or rough edges rather than the desired rounded shape. Thus, the method of filing in one direction not only ensures a smoother finish but also promotes healthier nails overall.