My primary goal in mentoring, as in teaching, is to make you into a responsible, professional, altruistic, and thus generally worthy citizen. With regard to research, I would like to strive for autonomy, mastery, and purpose: I aim to give you the autonomy in shaping your research, while emphasizing rigor and always becoming better at generating cool and correct insights (mastery), and to remind you of the greater purpose our efforts are serving, namely to expand the knowledge of human civilization. I think this includes both generating and disseminating knowledge, as a responsibility towards the society we live in. I believe this includes becoming an advocate for science and truth,
A secondary goal is to help you with your career goals and to support you as a person and keep you mentally healthy. I highly encourage you to explicitly discuss both of these items with me at any time. You should realize that I know very little about careers outside of academia though (see below).
I've divided this into sections, as below; however I actually recommend you have a quick look at all the sections, to get a feeling for what's coming or what you should already know. Below that are general career-related thoughts.
I do not assume that everyone who works in my lab is aiming for a full-time career in academia. What I do assume is that you are an adult who is responsible for taking their life into their own hands. There are certain things you can get from, for example, research experience, or graduate school, and other things that you cannot. It is worth regularly returning to the question of what you want from life and what you want from graduate school/research experience. I would encourage you to frequently check in with me on these topics.
One key element to realize is that graduate school is not professional training: it is not really training you for any particular job - all of that kind of learning typically happens 'on the job' (whether you eventually become a data analyst or a professor or something else). Graduate school does train you in how science is done and makes you into a scientist at least for the duration (even if you choose to do something else afterwards).
The reason I am saying all this is that you can not expect graduate programs to channel your activities into what you need to get a job, and much less to force you to come up with a plan for what job you want. Graduate school is for people who have answered these questions already and decided that graduate school would be a good first step to getting the job they want (even if that first step is about figuring out if they do want it); or for people who just love research a lot and are willing to spend a few years on it (regardless of whether it helps with what comes after).
To some degree, all this is also true for College - i.e. if you are an undergraduate student, you should realize that no-one can take away your responsibility to figure out what you want to do with your life, and how to get it. But, lots of people, including your colleagues and advisors in the lab, are very willing to help you answer these questions if you ask - but it is just that: help based on their own experiences and knowledge.
A CAREER IN ACADEMIA
A key piece of advice is to not assume that any job is like what it looks like from the outside.
This means that by far the most useful thing you can do it to talk to people who actually hold the job you are going for, and to ask them directly about what they see as the main perks and disadvantages, and how they spend most of their day. I talk about this for the job of 'professor' from my perspective below, but it is also important to realize that there are many different versions of what a 'professor' might be or do; and the benefit of that career is that you should have access to lots of people who hold that type of job, so you should be able to get lots of input.
Life as a professor: So I knew I wanted to be a biology professor at least since I was in 5th grade, and I never really considered any other career. And, it is in every way the right choice for me: I find it to be fun, rewarding, flexible, well-paid, and interesting. This is to say I work fewer hours than I would in a management-type job or if I had founded my own company, but I have more freedom both in when and what to do for my work than most jobs. This job is in my experience more compatible with family life than most other jobs that pays equally well, and allows me more time to learn, read, and pursue my interests than pretty much any career job does, while still being incredibly secure.
I say all this because you may hear others say that being a professor is extremely stressful and competitive. Now in my experience getting a tenure-track job, and tenure, is indeed those things, particularly because of the uncertainties involved, the short-term contracts, the two-body problem, etc. But, this is all the case for many well-paid jobs, and I think most people who argue this are not using the correct comparison group. Talk to some of your friends or relatives who have jobs in the >$70K range (a typical junior-mid-level salary at R1 universities these days). How many vacation days do they have? Can they just come hours late on a given workday to run errands or tend sick kids? How often do they get reviewed by their boss, how much job security do they have, and how likely is their company to hire their spouse?
You might want to find out more specifically what salaries you can expect at institutions/jobs you are interested in. For all public universities and government jobs, this information is public record, i.e. you have a right to it, but it may be hard to find. For the UA, the budget book has all the information, but there are easier ways to search for salaries described on the library website.
Once you manage to clear the tenure hurdle, you really should not assume that life is all work and no play for professors. [SMBC has this to say about 'Publish or Perish'.] One person's assessment of how much professors work (by Chris Buddle) is here. Personally, I will say that I have a hard time believing the total hours cited here, at least for professors in biology at the UA. I think there is a culture of overreporting, and focusing on those weeks of the year that are most busy. Tellingly, the author of this particular blog does not want to tell us what his total actually is. It's also important to realize that there is a LOT of variation in how people prioritize, how efficient they are, and how low-hanging the fruit in different fields are. Most people will say that they become a lot more efficient over time (undergrad to grad school, or before kids to after kids).
More blogs/other opinions on life as a professor: Another blog on this and how to stop worrying about tenure (AND manage family life) by Radhika Nagpal. And more on managing family life as a professor. More on women in the sciences here and here. Advice from an 'old' prof looking back. Check the blog by Joan Strassman to see the views of a senior professor on what matters in managing a research career with some life balance, finding good research topics, writing and presentation skills, etc. For example: choosing long-term research goals (to get tenure). Terry McGlynn has a blog more focused on 'small', i.e. teaching-focused, institutions. For example, I like 'Bandwagons are for big labs', 'Startups at teaching-focused institutions'.
I don't want to say there are not things that are very stressful about the job (ungrateful students, grumpy/ignorant reviewers, unrealistic departmental expectations, tedious administrative tasks). Those are not under your control. But I would say more of the just workload-related stress is ultimately under your own control than in many other jobs. And for the purpose of choosing a career, I'd suggest you should ask your parents, or other people who have been in some other career for a while, whether they don't have those kinds of issues. In my experience academia mostly contains highly motivated students, helpful and intellectually interesting colleagues, reviewers and grant panelists who genuinely want to make science better.
MENTAL HEALTH ADVICE
Prevention and taking these issues seriously is key. Generally, in my opinion, the two most important things you can do here are first, to 'sharpen your saw' (habit #7 from famous Covey book). What this means is to realize that it is important to stop before you overwork yourself, and to take warning signs seriously. Second, both anecdotally and based on research, people also remain healthier if they have good relationships and social support networks. The latter should not be underestimated. I really recommend making actual friends both among other students/scientists at your level, if needed in other programs, as well as among your science colleagues (eg. at conferences); think of this as an actual assignment that's part of the job (which it actually is even not related to mental health).
Some other links/articles: Accepting that you have to manage your own mental health. Strategies for stress.
Universities also have various professional resources, e.g. counselors etc. At the UA, you can go to CAPS, which is located just at the east end of Lowell St. in Campus Health, on the 3rd floor, 621-3334, and they have walk-in hours M-F 9am-4pm. Do not be shy about discussing any problems with your advisor or colleagues. In my lab, I never expect you to share personal details, but if you feel you are nearing breaking point it would really be helpful if you shared this with me so we can perhaps lighten your load or rearrange projects, priorities, or time plans.
You (or I) may not agree with every single point made here or by the linked pages listed, and indeed some may not apply to your situation. But take them seriously nonetheless - all of them are based on real experiences by people who have been in this business for a while.