Mentoring 101: Let's talk about the money

It is a major goal of my blogging efforts to get postdocs, and to a lesser extent graduate students, focused on the career demands that will hit them upon making the transition to independent research positions. I try to encourage people to learn about grant mechanisms, grant writing and grant review issues even before they are permitted to submit grant applications. One reason is that it is a big topic and the sooner you start chewing it over, the better. A second reason is that these understandings can help to shape your plans for the future, which may make some changes in how you behave now.
In a recent post, Dr. Jekyll & Mrs. Hyde has brought up an obvious issue that I can’t recall having blogged about before.

Although Dr Hyde and I have both had fairly forthcoming advisors on topics large and small, the one topic that we find we know nothing about is:
How much money do our advisors receive each year in the form of grants or other funds, and how is it budgeted?

She then goes on to ask:

So this is an etiquette question. Is it ok to approach my advisor and say, “I’d like to learn a lot more about lab budgeting and management so that I’m better prepared for an academic future–can you give me the approximate annual budget for this lab and tell me what percent of it is spent on various costs?” Is this rude, like asking about his salary? Is it just awkward, like asking about his dental work?