Then go when the time comes, whether you feel like it or not. That's the whole method.
It borrows from behavioural activation, a talking treatment for depression built on one idea: plan the activity, then do it on schedule, not when the mood arrives. With a trained person over several sessions, it works about as well as CBT, the talking therapy that works on thoughts and habits. In a trial of 440 people, less experienced staff delivering it did as well as CBT, for less money. Evidence: solid
What you're doing here is the do-it-yourself version, and that's a smaller thing. A few small, short trials of self-help versions looked promising. That's all. Evidence: worth trying A calendar entry isn't the treatment.
Why an old thing and not a new one: it's cheaper to start. You know where the gear is and who to ask. When you're flat, everything feels like it costs more, the effort cost. Evidence: worth trying
This isn't the same as one real win a day. That one is about finishing a task. This one is about going back to something that used to matter to you, before it feels like it does. If it feels like nothing the first time, read test the want, not the like. If a few weeks of this changes nothing, go through the two questions.
Same theme: A lift
A lift
Green space, weekly
Once a week, somewhere with trees or water, for an hour or more. Walk, fish, bike, sit.
1 hour a weekEvidence: decent
A lift
One creative hour a week
Draw, play, build, cook something new, write. An hour, no goal, nothing to show anyone.
1 hour a weekEvidence: worth trying
A lift
One real win a day
Every day, finish one thing you can point at. A fixed hinge, a sent email, a run. Write it down at night.
no timeEvidence: worth trying