If your rental unit is a condo unit, you'd better buy the rental insurance. If the tenant damage the structure of the unit and building, you will definately be better off to have coverage. You may want to limit the number of students to 2, or unless they belong to the same family because I think 2 is the max. The tenants also need to buy tenant insurance.
It is also better to get the rental insurance from the same insurer as your primary property.