Though it took several years and numerous unsuccessful trials on cadavers that had volunteered for medical experimentation prior to death, the process was finally perfected in 3,997 BBY. The process was not without drawbacks, however; it was very expensive, and it was highly-dependent upon a number of factors. Bodies had to be fresh, or else preserved in stasis fields, and the brain in particular had to be relatively undamaged. Despite the negatives, those who underwent the procedure generally saw an increase in life span and quality of life. Perhaps the most famous example of a successful case was that of Marine captain and Jedi Knight Laera Reyolé, who only realized her Force-sensitivity after having been put through the treatment by the enigmatic Jedi-turned-Dark Lord Revan.