When applying for an ED-Visa for International University in Thailand, I am asked to list the duration of study period, given the option of a start and end date. Should I make the end date for when the degree is finished (4 years later) or the end of the first year of study?

I don't understand if this Visa must be re-applied for again at the end of each school year or if one visa can be renewed for 4 years consecutively.