Why are so many people holding more than one job these days (from CEOs to professional athletes to regular people)?
Income — Perhaps the biggest benefit, of course, is that it can increase your income.
Variety — Second jobs often don’t pay much, but they enable the worker to learn new skills, meet new people, and do interesting work.
Diversification — Having more than one employer or source of income can reduce the financial and emotional impact of losing your primary job, and may enable you to more quickly recover by growing the secondary job.
Flexibility — For some, having two part-time jobs offers the same income as one full-time job, but enables them to fulfill other role duties like picking up their kids from the bus stop or caring for an elderly parent.
Risk Elimination — Many entrepreneurs began building their business while they still maintained their day job. Knowing that the first couple years of a startup can be very lean, maintaining the primary job until things are more stable reduces the risk of entrepreneurship.
This is an excerpt from We: How to Increase Performance and Profits Through Full Engagement by Kevin Kruse and Rudy Karsan.