Exactly _what_ is different about being a graduate student vs. undergraduate? (Think: day-to-day)

(I am in linguistics and my master's degree was heavily research-based.)

I remember an undergrad professor of mine cautioning her class as follows: "Being a graduate student is very different from being an undergraduate student." Three months into my MA, I found myself thinking, 'no it isn't', but six months into my MA, I thought, '...okay, yeah, it totally is'. The skills that the degree aims to impart are quite different: going to classes starts out feeling similar, but over the course of any graduate degree it should evolve from 'building knowledge base' to 'reading the literature critically and coming up with new ideas'.

To me the biggest difference, psychologically speaking, aside from the big step up into the unknown (= major original research) was in terms of project scope. As an undergrad, I could run myself out of homework for the day, or the weekend, and then relax, because I'd dealt with everything I needed to do. Beyond the undergraduate level, that kind of stops happening. A grad-student in any program with a research component always has that work at least in the background, and projects are enormous in comparison to most undergrad coursework. You can't run yourself out of work for the day, or for the weekend. The research is ongoing; there's always more to be done. It's a marathon rather than a bunch of little sprints. You have to keep coming back to a thesis and picking up where you left off. At the graduate level you have to develop have a sense of how to work on something a little at a time. And how to put it away and to (try and) do something fun once in a while.

first, it's hard to group all grad programs singularly. many programs have three sort of "classifications" of graduate students based on the degree they are seeking: M.S. non-thesis, M.S. thesis, and Ph.D. each of these classifications will have a different "day-to-day" and purpose.

M.S. non-thesis option is not terribly different from undergrad. you're taking classes, and that's about it. hours spent per week will be governed by the amount of homework/assignments you have in class. hence, hours spent per week will be similar, maybe slightly more intensive, than undergrad. end game for most M.S. non-thesis students is to work in industry doing similar job functions as a B.S., but at a slightly higher salary.

M.S. thesis option will involve 1-2 courses/semester, plus research directed/guided by your advisor. the research will require a significant time investment, and a lot more creative, independent thinking than courses. that is, courses are VERY guided since there's a clear set of expectations such as homework sets. research, on the other hand, requires you to think critically about what you're doing, analyze your results, interpret enough that you can explain those results or devise next steps to help you explain unexpected results, etc. career path for many M.S. thesis students is sometimes industry, sometimes a research lab-type setting.

Ph.D. involves 1-2 courses/semester for just 2-3 years, plus a significant amount of unique, independent, first-of-a-kind research. typically the research will be guided by your advisor for the first couple years, then they'll expect that you eventually become self-guided. at the end of the Ph.D. you should be the world's expert on that topic. but, this doesn't come without a cost -- many successful Ph.D. students log well more than 40 hours/week on their research alone (course work is done on top of that). the biggest misunderstanding students have is assuming that coursework is important in the Ph.D., and spending too much time trying to get "A's" in courses. the research is extremely crucial, and should be the focal point for the student from the get-go. courses are there to help you learn topics that will inform your research. career paths for most Ph.D. graduates is independent research in academic, lab, or industry settings.