I've had similar questions on this. Good question. This is my take:
The three fold model for evaluating daily work is this:
- Doing predefined work (from your calendar and next actions lists)
- Doing work as it shows up (reactive, unplanned tasks)
- Defining your work (processing inputs and deciding what they mean)
On #1, Doing predefined work:
If following the 2-minute rule to the letter, you wouldn't have any in your predefined work (actions lists) since you'd have already done them.
On #2, Doing work as it shows up:
You are free to do the 2-minute task if you'd like, or not do it if you don't want or are focusing on something else. For example, you may be practicing the piano, realize you need to start the dishwasher which takes two minutes, which you could either do if you'd like, or not want to disrupt your focus so you write it down, and then get it when you have the time. During deep work, it can be counterproductive to break focus to do those tasks. Others may find it more relieving on the brain to do them then get back to the deep work. The key is you have the freedom to do, or not do, the 2-minute items when stuff "shows up".
On #3, Defining your work:
This is where I believe the 2-minute rule is meant to be implemented. You could say it occurs during processing, and once you determine the next action and if it's two minutes or less, then doing it is "technically" the doing phase. I wouldn't get too hung up on whether it falls under processing or engaging (doing) phase. It's going to get done so it doesn't really care what stage it lives in. Where I would be careful is saying that the two-minute rule applies during capture. When you decide to either do something, or capture it, is when you're living in "doing-work-as-it-shows-up land", and as I said above, you can either do it or not depending on whether you want to. But don't feel
compelled to do the two-minute item when it shows up because of the "two-minute rule".
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A nuance on #2 and #3, sometimes doing work as it shows up and defining your work seem to overlap. For example, when I'm around my house, I'm surrounded by "work that shows up" in the form of toys needing to be picked up, laundry, dishes, etc. I sometimes will do the two minute item when it shows up as a one-off,
but I also like to think of "picking up" or "doing the dishes" or "folding laundry" as clearing an inbox and is therefore "defining my work". Each item needs to be picked up and "processed". If there is not action, I need to metaphorically "file it" by putting it in the toy bin, or in the dishwasher, or the clothes drawer. (This is akin to Dana K. White's decluttering "take-it-there-now" method.) Once in a while there is a next action when processing like "I need to iron this shirt before I can wear it". So I capture it. I've had great success in thinking of decluttering as "clearing an inbox", and applying the two-minute rule accordingly.