I also prefer one next action per project.
I find that most projects have multiple possible pathways, and multiple independent threads that could be followed concurrently. My logical conclusion was that I should populate my action lists with as many as I could think of. However, this led me to procrastination. When in my calls list, I would put off the call. The call would be better after I had run the errand. Then while running errands, I would hold off on a purchase because it would be better to talk to a collaborator first. This sort of procrastination held me back on many projects.
Now, I realise what I was doing was avoiding making a choice. Because of this, when making a next action decision, I look for the single next action that will progress the project. If there are multiple possibilities, then I make a choice.
Importantly, when I look at my lists and see actions, I know that those actions are required (not optional) to progress a project.
This works well for me for most of my projects. I do have one or two that have large independent strands that have a next action each.
