I had some great conversations with friends from my interdisciplinary cohort, all of whom are already finished with or finishing their degrees at UBC. I've been on a 6-year plan for most of grad school, and soon I'll be starting that 6th year. That means I should be thinking about finishing. But I have to say, right now I feel like I have more than a year's worth of work remaining. I asked my friends for advice.
The best answer? You have to decide to finish. Many people think they'll know when they get there, and they just keep working, thinking they need a little more (or perhaps their advisor thinking they need more), and they continue on. Both of my friends who finished were extremely driven and they both dealt with advisors who dragged their feet one way or another, but they were committed to finishing by a certain time, and they made it happen.
I think I'm at the point where I need to decide that I am going to be finished one year from now. Oh my gosh, I got chills down my spine when I typed that. Ok, so maybe it will be June or July or August next year, but I need to decide that I will finish in 2013.
There. I said it. I've decided. One year left.