How many people do you know who have multiple doctorate and master degrees?
We commonly see MD, MPH (or DO, MPH)
I also know a few physicians with MD, JD
We see physician scientists with MD, PhD (or DO, PhD)
I also know quite a few people who have MD, MPH, MBA
It's less common to find someone who have MD, PhD, MPH, MBA
Where's the limit? There is none! So, what are these people doing with so many degrees? By the time you graduate with all these degrees, you won't have time to work because you'll be ready to retire!