Over 10 years now since I let GTD go. There was no good reason but a sketchy excuse, "my job changed and the chaos was so overwhelming that I didn't have time to write anything down much less use a calendar"! What's illogical is that I started GTD in and around 2000-2011 and I let it go!?
Well, I got on the GTD bandwagon about a month ago and 'refuled' my life. I have one major relief, I am fully retired. But I am still in need of tracking all the details of things to do and be done. And they aren't all doctor appointments! But as you, David, have reiterated many times, I now know what I am not doing right now. And that is the first freedom I experienced. After that, was a feeling of control, not an illusion of chaos. I am embracing my tools and my style. I am a good student of yours teacher! Thanks for all of your dedication to assist and share with others who really want it. Gazillions of people need this, especially our future adults. For what its worth GOOGLE CALENDAR, TASKS, KEEP, DOCS, DRIVE, RECORDER & SHEETS work for me. I also really like journaling as well. Both digital & paper.