Projects are things that I need to do a series of steps for. A single action is something that cannot be broken down into a smaller task but in my world a single next action can actually require several or many work sessions to complete. So I don't use the time to complete in a single work session as my criteria for whether something is a single action or not.
For example: I would never put on a next action list weave 3 inches on twill fabric unless I was stuck and needed a kick in the butt to get moving on that project. My project would be Weave 10 yards of 2:1 twill fabric from lace weight grey blend yarn. There are a lot of steps to that, measuring warps, warping the loom, filling quills with weft but once a lot of the prep work is done the major task is weave the fabric. The time it will take is very long but there is nothing else to do on that project until the weaving is done. It might take me 180 hours of weaving time to do that action and I sure can't do that in a single step but it would still be my next action.
Oogie McGuire - Mac, iPhone & Omnifocus
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Paonia, CO USA