When it does come
Sooner or later one of the ticks in your log will be a big one. The scan isn't clear, or the redundancy is real, or the phone call does come. About one worry in eleven came true in the study in chapter 4, and over a lifetime that adds up to a fair number of bad days. A book about worry that ignored this would deserve to be thrown across the room.
The first thing the habit will say is "See? I was right to worry." It's worth answering this properly, because it's the moment when a lot of people give up and go back to worrying full time.
The fact that it happened shows the concern was valid. It doesn't show the worrying helped. To judge that, ask what you actually used when the blow landed. Usually it was practical things, such as the savings, the friend who knew an employment lawyer, the insurance policy, and the early appointment that caught it at a stage when it could be treated. Every one of those was a step. Somebody took them at some point, in a few minutes or a few hours. Then ask what the rounds contributed. I mean the hundred evenings of rehearsal, and how many of their scripted conversations you ended up using. The usual answer is none, because the real event had particulars no rehearsal had guessed. The meeting was in a different room, with different words, and your reaction wasn't the one you'd practised.
Often the event wasn't on the list in the first place. You worried for a year about your job and it was your knee that went. That shouldn't persuade you to worry more widely. What it shows is that lookout duty can't cover every direction, and general readiness does better. A person with some savings and a few good friends, in reasonable health, who has the habit of dealing with things promptly, is prepared for a great many events they never thought of. They're better prepared than the person who spent those years on detailed rehearsals of a few.
Once it's happened, it's no longer a what-if. You now have a problem, and as chapter 7 said, a problem comes with particulars. There are people to ring and forms to fill in and decisions with dates on them. The rule from chapter 11 still applies, and now there are plenty of steps to take. Many worriers find, to their own surprise, that they're good in a real crisis. They're calm and organised and useful. I don't think that's a paradox. A crisis gives the mind what worry never does, which is something definite to work on.
There's a harder case, which is the long wait. You've had the biopsy and the result takes two weeks. The company has announced cuts and the names come out next month. Your mother has been given a diagnosis that will unfold over years. Here the bad thing is partly real already and the uncertainty may last a long time. This isn't the everyday worrying the rest of the book describes, and I don't want to be glib about it.
A few things still hold. Take whatever steps exist, and take them early. That might mean the questions written down for the consultant, the CV brought up to date, or the conversation with your brother about who does what. Keep the slot, because a long wait produces more what-ifs than any other situation and they'll fill all the hours you allow them. And don't expect to feel fine. The bar exam study in chapter 6 found that nothing people tried made the waiting itself comfortable. It's normal to feel dread during a real wait for serious news, and it doesn't mean the method has failed. The aim in those weeks is modest. You want some hours each day when you're in your own life and not in the waiting room, and you won't get more than that.
Be careful, too, about what you say to yourself afterwards if the news is bad. "I should have worried more" is almost never true. "I should have gone to the doctor sooner" is sometimes true, and what it regrets is a step you didn't take. If you feel any regret when you look back, you'll nearly always find it's about a step.