From what I remember about them, you will especially get different results if you test again within a short time span. After a year there should only be differences due to other circumstances, like stress or other stuff that influences the workings of the mind.
My own experience is that you can get significantly different results when re-testing, even within a short time frame.
From what I remember about them, you will especially get different results if you test again within a short time span. After a year there should only be differences due to other circumstances, like stress or other stuff that influences the workings of the mind.