Luisa/Laura: schedule in time for interruptions then too. I’m a system adminstrator at a university, I basically support directly about 20 faculty and 65 grad students (we have 60 / 200 or so total, and the rest are “allowed” to talk to me too), as well as the occasional staff member question. Basically, I get interrupted a lot, so I know where you’re coming from - but if you allow some percentage of your time (only you can say how much is appropriate, but I go with 30-40%) for interruptions, I find that helps. I also schedule such that if I think a task will take me 30 minutes uninterrupted, I schedule it for 45 minutes or an hour. Not perfect, but it helps. I’ve also learned that most people don’t take it personally if you tell them “sorry, I can’t do that right now, but how about at 1pm?” sorts of things.

If they do take something like that personally, you’ve got problems that no amount of scheduling or GTD in the world can help you with.