The శుక్ర vrat is kept on శుక్రవార — traditionally one meal after sunset, without salt. It is the household remedy for a weak శుక్ర, and unlike a gemstone it cannot be kept against your chart.
The weekday fast is the household remedy — kept on the graha’s own day, usually one meal after sunset and no salt. It is as much a discipline as a ritual: the point is the weekly act of restraint, held long enough to mean something.
The Friday fast is vegetarian and sweet-tasting; the sixteen-Friday vow is the traditional observance for an unmarried woman seeking a good match.
A weak Venus shows as difficulty in marriage, restless dissatisfaction, and money that goes on pleasure. The remedies steady the relationship rather than the bank balance.
శుక్రవార. Fasting, charity and mantra japa for శుక్ర all belong to that day.
The mantra, the weekday fast and the charity are safe for anyone — they address శుక్ర without amplifying it. హీరా is not: a planetary gem strengthens whatever the graha is already doing, so it needs a chart reading first.