Schedule Task

Question

Dear all, i am Danish Habib and i am developing a web application , in that i have to assign a maximum of ten days to user to submit his data after that time his visible bit becomes false and he will not be able to submit his data,What would be the mechanism ,If I calculate the days on that specific page and based on the days if i send a email as remainder,then this code would be run every time when the page hits,i do not want that the if the pages hits 1000 times then 1000 emails would be sent to him its bad. what would be the alternatives ??