I really bought into GTD a few years ago when I had become overwhelmed by my to-do list. I found a really good book on implementing GTD within Outlook, which suited me as I use Outlook with Office 365 on a daily basis. I read all about TSW and attempted to implement it in Evernote. However, as well as being rather complex, it felt very unnatural to be saving emails into evernote rather than staying in the place I was already using - i.e. Office 365. However, I really liked the Now, Next, Soon, etc categories. So now I have modified my Outlook GTD implementation to incorporate the 'when' as well. I also added 7-projects and changed !daily to !repeat. I always found the contexts to be a bit redundant for me: most of my time is spent in the office so I am always able to be 'at my computer' and 'at my phone'; my commute to work is about 5 minutes if I drive and only 30 if I walk. I think that the context idea works better for those who spend quite a bit of time on the road. I do use errands and at home, but as it is difficult to find an android calendar that allows you to call up tasks by category, I tend to use Google Keep for my shopping list and my list of tasks for the garden at the weekend. I still do the weekly review and go through all the whens. if I have more in Now and Next than I can reasonably complete in a week, then i know I need to re-negotiate with myself, or someone else and move some tasks into soon. Some tasks end up in the calendar if they have to be done on a specific day. It is working for me.