I have a terrible guilt complex these days. No matter how much I get done, it almost never feels like I'm doing enough. I suspect this has something to do -- a lot to do, actually -- with how poorly I spent some of my summers during grad school. I wasn't a complete waste of space (I did do work), but I wasn't all that effective: I did a whole lot more reading than I did writing, and I did very little in the way of learning how to publish. And I suspect there are more than a few grad students reading this blog that know what I'm talking about. ;)
Accordingly, I thought it might be good to open up a discussion on what everyone thinks constitutes a productive summer. Doubtless this will mean different things to different people (not everyone works alike, not by a longshot). Still, I think it may be helpful to discuss what people in various circumstances -- e.g. grad students and early career faculty -- consider a "summer well spent."
Having not been productive enough as a grad student, I guess I'm apt to think that after a couple of years of grad coursework, a "good summer" for a grad student involves either (A) finding a single paper that you've written that has some promise and trying to work it into a publishable piece, or else (B) drafting up several shorter (3,000 word pieces) to send out to conferences. If you haven't done one of these things or the other, you might want to consider your summer "not productive enough."
On the flip side, as a young faculty member I won't feel like I've had a "good summer" unless I've drafted up a handful (i.e. at least 3-5) full-length papers I feel good about. A few years ago, when it took me many months to draw a single paper into shape, this number might have struck me as outlandish, but when I look around the discipline at early career people who seem to be doing well it seems like this kind of productivity is the norm. This is not to say that it's not possible to do well in the profession by producing work much more slowly and methodically (as I'm sure some do). The primary reason I think "being productive" tends to involve producing so much stuff has to do with the sheer probabilities involved in the publication game. Given that good journals reject 9 out of 10 papers, writing only a paper or two a year is a recipe for trouble. Or so it seems to me. But what do I know? Maybe I've got it wrong. I'd be curious to see what everyone else thinks!