"I had the whole afternoon free" and "I had the capacity to do that in the afternoon" are two different statements. Almost every planner tracks the first one and none of them track the second.
That gap is where most ADHD plans die. Not from overcommitment in hours — from overcommitment in activation cost.
The 10am plan and the 3pm executor
Plans are written by the version of you with the most capacity — usually early, usually after coffee, usually feeling briefly like the competent one. They are executed by a different person entirely.
The 10am version writes "draft the proposal, chase the invoice, call the accountant". The 3pm version opens that list, registers three high-activation tasks, and closes the laptop. Nothing was unreasonable. It was written for the wrong person.
Sorting by activation cost
Not every task costs the same to begin. Filing receipts and making a phone call to someone who might be annoyed take similar minutes and wildly different amounts of whatever it is you run out of.
Sort tasks into three bands by how much it costs to start them, not how long they take:
- Low — can be started while tired or distracted, needs no decisions
- Medium — needs a clear head but no emotional exposure
- High — social risk, ambiguity, or a first move you have not worked out yet
Then the day starts with one question — what have I got today — and the surface only shows the band that matches. Not a filtered version of the full list. The others are not visible at all, because a visible high-activation task on a low day is not an option, it is an accusation.
The capacity cap
The other half of this is a ceiling. ADHD overcommitment is not only a planning error — it is frequently an RSD-driven yes that happened before anyone calculated the cost.
A daily cap is a number decided in advance, when you were calm, about how much the day can hold. When the day reaches it, something visible says so. Without an external stop signal there is no stop signal, because the internal one does not fire reliably in either direction.
You had the time. You did not have the battery. Those are not the same sentence.
Stopping cleanly
A clean stop is a skill worth building deliberately: end the session at the boundary, write the single next move while the context is still in your head, and close it. The next move written at the point of stopping is worth an hour of the next session, because it removes the initiation cost from a cold start.
What you are optimising for is not the productive day. It is the day after the productive day — the one that usually disappears.