When need "DoEvents" and/or "Sleep"

[rpool]

I have question:

When need "DoEvents" or "Sleep"

any advice if this example, need "DoEvents" ?

Private Sub Command1_Click()
Dim a As Integer
Dim b As Integer
Dim c As Integer
Dim d As Integer

a = 6
b = 7

c = a + b
DoEvents

d = c * c
DoEvents

MsgBox d



End Sub