The paper is addressed to the developments of the variable-energy positron annihilation spectroscopy (VEPAS) in the last two decades. It shows the limitations of the methods and the requirements for the near-future progress. The main task for the positron community is to establish high-brightness positron sources to be operated as user-dedicated facilities. Furthermore, the paper demonstrates the depth- sensitivity enhancement of defect profiling by VEPAS when the sample is removed stepwise by ion etching (sputtering). Using this technique, the long-standing question of the origin of gettering centers in the Rp/2 region in high-energy silicon self-implantation could be answered. Small vacancy clusters were found to be the gettering sites at this depth.