Which should be avoided during the filing process of nails?

Using a very coarse file should be avoided during the filing process of nails for several reasons. Coarse files can create excessive friction and can damage the nail plate, leading to splitting, peeling, and breakage. They can also cause discomfort to the client, making the nail care experience less enjoyable. Instead, it is advisable to use files with a finer grit that can smooth the edges without causing trauma to the nail bed.

The practice of filing in one direction only is recommended as it helps to minimize damage and split ends of the nails. Similarly, the use of an emery board is commonly accepted in the nail care industry as an appropriate tool for finishing the edges of nails. Finally, filing on both sides of the nail can help achieve a uniform shape, as long as it's done gently and not excessively, which is acceptable when proper techniques are applied.