There's a treacherous moment in all development: when it starts working.
The experiment landed. The behaviour shows up. Someone has noticed. And right there, many people drop it. Mission accomplished.
Three months later, the old pattern is back in its place, quietly, the way things that haven't been integrated always come back.
The fourth phase exists for that: integrating. Turning the gesture into part of you, not a performance you maintain. And it has a different logic from the previous phase. It's no longer about testing; it's about sustaining and raising the bar. What was an experiment (holding the silence in one committee) becomes a practice: holding it also when the issue touches you, also with the board, also on a bad day. The competency is incorporated when it stops costing so much. Until then, it's a correct behaviour sustained by effort.
How to do it well: with cadence, not intensity. Spaced check-ins. Small increases in difficulty. And special attention to relapses. Because there will be relapses. A relapse isn't the failure of the process; it's part of the process. The difference between before and now is that now you see it while it happens, you have a name for what fired, and you know the way back.
There's one integration signal that never fails: other people. When someone on your team mentions the change without being asked («you've been different in committees lately»), the behaviour has crossed from effort to identity. The outside mirror confirms what the inside one suspected.
And one final decision remains: when to change focus. The honest answer is: when this competency no longer needs your deliberate attention to show up. Then you go back to the list, look at what your moment is asking for, and choose the next one.
Development doesn't end. It changes front.