I was on the 8-year plan...
I love learning, and couldn't decide on a single major. First I was planning on CS / Math, but wound up taking a physics course, asking the right questions, and the professor hired me to do research for him and put me on the honors track. As long as I was matriculated as a physics major, I had a scholarship and a pay check waiting. I also happened to love it. Because my University didn't allow more than two courses to overlap between majors, I wound up taking enough math courses to otherwise have majored in it, but it didn't count.
In my senior year, I took philosophy to satisfy a writing requirement. It was analytical philosophy. Logic and reason was valued above all. We discussed the problem of other minds, philosophy of religion, and a broad array of other things I had always pondered. In fact, I thought I must have been the only kid in kindergarten wondering how I could be certain that my parents were actually conscious beings and not just bags of molecules. How could I know for certain that they had a mind and consciousness in the same way that I did? When I found out that you could get paid to think about these things and teach people how to think, I was hooked. I decided to double major, and spent an extra year filling all of the requirements.
After graduating (the first time) I spent 6 months working at a local bookstore, deciding what track I wanted my life to take. I could teach high school physics, I could get a PhD in physics (though I was getting tired of seeing divs, grads, and curls every time I closed my eyes). I could become a philosophy PhD and later professor, which sounded like a dream job, but was difficult in practice to obtain.
Then it occurred to me that I didn't know much about biology and my own body. I would be stuck with it for the rest of my life, so I thought maybe I'd go to medical school. The problem was two-fold. I didn't meet the pre-requisite coursework for applying, and my grades were not competitive (I never handed-in homework. I studied things for their own sake and not for the grades.)
After watching a few UC Berkeley lectures on chemistry and biology, I decided I loved biology. I returned to my University to get a degree in some form of biology. I wanted to learn it very well, get great grades, and I chose the hardest sub-discipline with the fewest students: molecular biology and biochemistry.
I was amazed to discover that when I actually tried and cared, I was at the top of every class. I graduated again, with a 4.0 and applied to medical school.
Amazingly, even with these credentials, a large body of research, and a very competitive MCAT score I was still only accepted to a few schools.
I wound up getting into a combined MD/PhD program, which was an additional 3 years over regular medical school, but allowed me to conduct research. It also came with full tuition and a stipend.
I'm now in my third year and doing research at the NIH. I have five more years until I graduate for the final time.
In retrospect, I could have forgone almost all of college and just audited the courses that interested me. In fact, I believe that college is of only marginal value to most people. Most of the skill set I acquired I learned in high school, on my own, with books and computers.
Without college, however, I would never have gotten into medical school. It is definitely necessary for some things.