In all the pages and pages of advice given to grad students, postdocs, and starting faculty, I think one item tends to get left by the wayside, or at least is not explicitly stated.
You always underestimate the time spent managing a project from start to finish.What I mean is this: problems (at least in theoryCS) are easy to state, and fun to work on. Sometimes they take a while to crack, and sometimes they give up their secrets easily. But the time you spend on any given project is much more than the actual time spent thinking about it. There's
- Writing up the first few drafts
- Iterating to get a polished submission version
- (...this step repeats until the paper is accepted)
- Preparing the final (often very cramped) version
- Making slides for the talk/talks you'll be giving
- Preparing a full/journal/arxiv version, which often involves simplifying, rewriting, reproving, adding new references, etc etc.
- Submitting to a journal, and waiting endlessly for updates on its status.
- Addressing reviewer concerns, and resubmitting
- And finally, getting it into print.
It's not so much the time involved - papers tend to time-multiplex quite well so you're usually in different phases of the above sequence for different papers.
It's more a matter of motivation. I don't think I'm the only person who feels this, but once I have some nice results, and especially if there isn't follow-on work to be done, I get bored with a paper. Having to deal with it for months and months afterwards is then as excruciating as killing off zombies that keep coming back (not to mention what happens if it keeps getting rejected).
So be careful when you choose a project: make sure it can last through at least a few papers, or you'll be spending a lot of time cursing yourself for the time you spend.