I had a lot of work to do to get ready for Ph.D. applications. I worked as a research assistant during the summer of my MBA program, and spent every remaining daylight hour in the Math Lab. The Math Lab at my school is in the heavily air-conditioned room where they used to keep the main-frame computer in the 1970s. It’s about 59 degrees around the clock. So, I spent 12-14 hours of each summer day dressed like Christmas, writing matrices and solving differential equations.
I was on campus working from about 7am to 8pm, Monday-Saturday, eating a quick lunch while walking to class or working out a homework problem. That translates to about an 80-hour work week, which is actually fairly light by some standards. Some of that was overkill, since the main reason I was taking the classes was to show I could get A’s. An A-minus or B-plus would have rendered the time spent a failure. I think I averaged 98% in the classes I took.
The point is, getting through a Ph.D. program is a lot of work. I’ve talked to professors who said they regularly spent 100 hours/week on school. Preparing for a Ph.D. program is also a lot of work. Some people just can’t continue working that hard and concentrating for that many hours each day. That’s also another reason why you have to really enjoy coursework and research–you’ll literally be doing it all day, every day. I do, and I do.