FOR NEXT is applied when the controlling variables are known at the outset of the loop. Until at the end of it. Traditionally, the body of a While loop may never be executed and the body of an Until loop will be executed at least once. VB allows placement of either at either end of the loop. It also allows an Exit Do which may be used with an If Then to immediately transfer control to the statement following the loop.
Good systems result when a Structured Notation is used early in the development.