The daily trimming of fingernails and toenails to make them more aesthetically pleasing could be detrimental and potentially lead to serious nail conditions.
This is according to researchers at the University of Nottingham who have devised equations to identify the physical laws that govern nail growth, and used them to throw light on the causes of some of the most common nail problems, such as ingrown toe nails, spoon-shaped nails and pincer nails.

Source: http://www.ereporter.com.ng/index.php/more-news/science-tech-news/item/631-daily-trimming-of-fingernails-toenails-harmful-to-health-research