Most of us are often asked to write a wide range of documents meant for consumption by very different people. Internal documents, manuscripts for society-level journals or those for "broader" journals, grant proposals, commentaries, evaluations, even blog posts. Each one is designed to reach a certain target audience. But does your writing style change to fit?
When I was a graduate student, my writing skills could best be summarized as "adequate". Yeah, I could write, but I was a buck knife when I need to be a swiss army knife. My mindset was that writing was meant for using the fewest words to convey the message in its most direct form. Great for writing abstracts, but not the most malleable tool.
As a postdoc I learned an enormous amount about writing, thanks to a supervisor who was relentless with red ink and an accomplished writer. I learned a lot about how to tailor my writing to the venue, even down to sentence length.
The concept of considering your audience always comes up most obviously for me when reviewing grants because it is common to read a few in a row that know what they are doing and then plow headlong into the mired thicket of a n00b proposal and wonder wtf just happened. And trust me, I've written those proposals.
The first few grant proposals I wrote as a n00b PI were The Best at the time. I got some feedback from senior colleagues and they all kind of danced around the thing I couldn't see: I wasn't writing to who I thought I was. I never put that together, realizing there was something the feedback was implying, but unable to grasp it. Looking back it's pretty obvious that I wrote the proposals like I was writing a paper for a small journal.
This is a topic that comes up all the time among the grant-advice blogs, but it can't really be emphasized enough: grant reviewers may not have any background in your sub-field. When I get grants to review I am often reading stuff about animals, which I think are the most boring group of organisms out there. A lot of people seem to study them, though, so I get to read about them. OTOH, since I don't work on animals, I often get to read proposals on Everything Else because my non-animal focus apparently gives me the ability to understand the other 99% of life forms. Far more often than not, there are major elements of a proposal I am largely unfamiliar with. This is not uncommon. At all.
This matters because if you write your proposal for someone in your field, you are making the life of most reviewers more difficult. Making life difficult for reviewers is going to come back to you in reviews that are less glowing about your work than you would like. My early proposals were not written for the audience that was going to read them and they got trounced, often for what seemed like obscure reasons that had nothing to do with the AWESOME SCIENCE! But I made the science more challenging for the tired panelist wading through a stack of proposals and that was that.
In an era where only a few proposals make the jump from the pile to the cash, writing for your audience is more critical than ever.