Oiling painted nails.
Cuticle oil is used to soften it, but it also helps maintain manicure for a longer period. It is recommended to lubricate nails with oil before contact with water, since it is it that is the main culprit of peeling varnish. A grease film forms on the nail plate to protect the varnish from water.
Do not file over painted nails.
If there is a coating on the nails, after processing with a file it will certainly begin to exfoliate. If there is a need to correct the shape of the nail, coat it with base and varnish again.