Simple Reminders app (happens to be Apple's Reminders) with "contexts" -- put in quotes because the way I use them may not be the way the GTD folks do. I have

Simple Reminders app (happens to be Apple's Reminders) with "contexts" -- put in quotes because the way I use them may not be the way the GTD folks do. I have one list of things to do, simple stuff like "pay bills" "feed cat" etc. I have sub-lists for every client I'm currently working with, or project I'm working on. I punch in just enough info in to the individual items to jog my memory as to what it was. Often times its something like "read that email" under the "!Client" list. I have sub-lists for every place I might be where I need to do something while I'm there, i.e.: @Office for Home @Home for Office @Cabin for Home @Home for Cabin If I'm at home and I remember I should bring my laptop home because I'll need it this weekend, I put that in "@Office for Home." When I'm at home and I realize I should bring the table saw home from the cabin to use at the house, I put that in "@Cabin for Home," etc. I bark things at Siri all day and at the end of the day shift things in to the lists they need to be in.