Just finished a massive "Weekly Review", a time of going through all my notes, papers, flagged emails, desktop icons and processing them to see what they are and what I need to do about them. It's also a time for going through my reminder lists, getting them up-to-date and making sure everything is heading a long as normal.
This time, I spent about four hours. If I actually finished my GTD refresh last weekend, it would have taken less time. I don't feel particularly cleaner or more productive yet, but there are definitely fewer loose threads. I'm also surprised by how many good ideas I've had languishing inside my head: I'm itching for a weekend or two to spend hacking and writing.