You can probably do it for a while. But, there is some sort of long term mental reserve that is depleted as we work. You would deplete these reserves more rap

You can probably do it for a while. But, there is some sort of long term mental reserve that is depleted as we work. You would deplete these reserves more rapidly and need to take a major vacation much sooner than if you had one job. The quality of your work would suffer at the second job as there are also reserves that are depleted daily and restored during sleep. In one sense you would be abusing the tools of your profession. There is a common admonition that "A craftsman does not abuse his tools". You must make your own decision, but I would never do it.