Over filing for nail extensions
Over filing of the natural nail can leaves the nail bed thin and weak, and not a good platform for enhancements. If the natural nails have been filed to thin, the enhancements will not adhere well to the natural nail and lifting can occur.
When the natural nail is thin and weak, it is much more flexible and so allows the enhancement product to bend more.
When the overlay is flexed too much, extensions can get tiny hairline fractures that lead to breakage of the extensions.
Very thin nails can also allow such as primer to get through the nail layers.
Also with over filing, onycholysis can occur and the nail can become susceptible to infection.