Can I use my security deposit as the last month’s rent?

No, the security deposit can only be returned to the resident after a resident has moved out.

Yes, as long as all the rent is paid on or before the 1st of each month. For example, let’s say we are in the month of July and your rent is due on August 1st. You may split your August payment as many times as you want in July as long as your rent is paid in full August 1.

Yes. You may pay as much as you want in advance.