Peter Drucker has a chapter on this in "Managing Oneself".
In summary:
Second or parallel careers
It’s relatively common for people to pursue second careers after their fist has peaked, or because they want to try and find success in a different area. This is especially true if your first career is in an area that is not the optimal environment for your performance – a second, or parallel career can offer the chance to make a difference somewhere else. A second career also creates options; you are less restricted when you have something else to work on.
Drucker identifies three ways to develop a second career:
- Start one – move from one organization to another, different sizes, different industries, or something else altogether
- Develop a parallel career – something on the side, or a part time job
- Social entrepreneurship – spend less time on the main job, and work on another activity (usually nonprofit)
In summary:
Second or parallel careers
It’s relatively common for people to pursue second careers after their fist has peaked, or because they want to try and find success in a different area. This is especially true if your first career is in an area that is not the optimal environment for your performance – a second, or parallel career can offer the chance to make a difference somewhere else. A second career also creates options; you are less restricted when you have something else to work on.
Drucker identifies three ways to develop a second career:
- Start one – move from one organization to another, different sizes, different industries, or something else altogether
- Develop a parallel career – something on the side, or a part time job
- Social entrepreneurship – spend less time on the main job, and work on another activity (usually nonprofit)
(Abstract copied from: https://willemharmsen.com/notes/managing-oneself/ ).