A change is a guess
You moved the walk to the evening because mornings were rushed. That is a reasonable guess. Maybe evenings work better. Maybe the real problem was that the walk was too long.
Without looking back, the guess just becomes the new plan, and if it doesn't work you are back to feeling like you can't keep a habit.
Why three days
One day says very little. A good day can follow a bad change and the other way round. Wait too long, and you no longer remember what you changed or why.
Three days is short enough to remember the change and long enough to see more than one try.
Keep it, or go back
If the habit happened more often with the change, keep it. If it didn't, go back to what you had before, or try a different change. Going back is part of the process: you learned that this change wasn't it.
Changing one thing at a time keeps the answer clear. Change the time and the size together, and you won't know which one helped.
How LilCoach does this
After a miss, LilCoach asks what got in the way and suggests one change that fits the reason. You confirm it, and you can undo it.
On Plus, the 3-day check-in shows how the habit went with the change, for example “At the new time: 3 of 3 days”, and asks: “Keep this change or go back to the previous setup?” If the change has not helped enough yet, it offers another adjustment or a pause.