Life extension is a talent that extends your life. Jack of woods beyond was kidnapped 100 years ago and he and Briar Rose are still alive. Yuba said in the Ever never handbook that many heroes learn this skill. It is presumed that plenty of other people use it too. Rafal and Sophie did not use this talent, their love kept them young and alive for eternity. The two school masters did not use this skill either, Rafal's love for Rhian (his brother) vice versa kept him young forever and vice versa.
Life Extension is used by many old heroes, like Jack (from Jack and the Beanstalk), to make their lives many years longer.