I used a plain text file for about 5-6 years before finding org-mode in 2009. Of course, I technically still use a plain text file since that's what Org uses,

I used a plain text file for about 5-6 years before finding org-mode in 2009. Of course, I technically still use a plain text file since that's what Org uses, just with some extra features that make organizing things specific to productivity easier. That said, I'm not sure I'd exclusively use a plain text file or even Org if I had to break my day down into as low as 15 minute chunks like this guy. I find the text-based approach to work best for longer-term planning/strategizing and just keeping yourself from forgetting stuff over the course of days. It also works better if you're already on your computer and using your text editor all day and/or SSH-ing into a box with the file. If I need to remember to make it to 4 meetings today at very specific times, something that pushes notifications and upcoming meeting warnings might accommodate that better. I've had meeting-heavy jobs, and split off the meeting management into Outlook (or similar) with good results. Useful info that flows out of meetings can still go into your notes to be organized later though. Then I make my GTD list "task-centric", meaning that it focuses on getting discrete activities started and completed, with less focus on times/dates. That requires some level of freedom to manage your own time though, so it's not for everyone.