Natural nails should be filed?

Filing natural nails from the sides to the center is the recommended technique because it promotes a smooth edge and helps to prevent splitting or tearing of the nail. This method allows for better control over the shape of the nail while reducing the risk of damaging the nail plate. Starting at the sides directs the file towards the middle, which creates a more even and uniform finish. It also helps to maintain the natural structure of the nail, promoting overall nail health.

The alternative methods, such as filing from the center to the sides or back and forth, can lead to uneven edges and may weaken the nails over time. Filing deep into the corner can cause traumatic injury to the nail matrix and is not advisable, as it can result in painful hangnails or other issues. Thus, filing from the sides towards the center is the most effective and safest technique for maintaining natural nails.