Why did you go to grad school?

I was interested in medicine and engineering biology. This gives a few different career options, but after a fair bit of time working in a lab. After briefly considering the doctor route, I decided research was the right direction for me. I'm still not 100% set on research for life, but a PhD opens a lot of doors that a BA in biology only nudges a crack.

My other option was computing, but the current state of the bay area leaves a bad taste in my mouth. I saw those 1.3k enrollment numbers in CS and recognized that competition is only going up in an industry with eyes mainly for recent graduates. CS / IT pays well but plateaus quickly. Biology tends to have a lot more breadth in its sectors and depth to its careers.

When did you go to grad school?

Last year - now.

What is a good reason to go to grad school?

You are passionate about pursuing a research question. You enjoy independence and open projects. You want to ask questions that might not be answered on a private company's dime.

What is a bad reason to go to grad school?

You want to continue education. You want to make more money. You want to boost your resume.

What is the best state of mind to start grad school?

Excitement, you will only become more jaded after day 0. Also have an idea of fields / questions you would like to pursue, but don't expect to stick to them if they turn out not so great.

What obvious and not so obvious things should I look for when choosing a program?

Look first at the careers the program will enable for you. Look at the area that you may be making connections in. Look at both the individual labs and the program itself. I picked my school because the program itself seemed more invested in the students. The other school I was looking at felt like it had less organization and less of a community, which turned out to be incredibly important when I decided that the three candidate labs I had were all bad fits. Both had a great neighboring industry presence and I would not have considered them otherwise. Graduate school is partially about passion, but you have also got to be realistic about what it will give you.

Ask the students in the program and in the labs what they really think about it. You'd be surprised how many world-class PIs have students who hate working for them. Ask the officials what the average time to graduation is. If they don't tell you, it's probably above 6 years. Computer / soft-science work tends to be a bit quicker / less time per week, but lab work is much slower. Most time-to-graduation averages do not partition by computer vs. lab work, so keep that in mind.

How on earth am I supposed to generate income while simultaneously committing enough hours to my studies? During the school year in undergrad I worked usually less than 10 hours a week.

If you are in a PhD program, you will make a small but decent amount of money. It's not enough to go out and buy fancy cars or have a family, but it is usually enough to support yourself. Some schools match their stipend to the cost of living in the area, some don't. Some provide graduate housing that students can afford, some don't. Don't ever pick a program that you think will send you into debt. And graduate school is usually a poor choice if you are already having money troubles.

Expect to commit to the program as a full time job while you are in it. I work 40-80 hours / week and would not be able to handle any extra work outside of maybe selling hobby items online or maybe part-time tutoring / consulting in later years. This time goes to teaching, classes, and research year-round, with free time going first and foremost to activity that take care of my health.

Masters are a different beast that I can't really comment on.