3. Deliberately break one harmless routine
The third habit is not something to add to your routine. It is something to interrupt. People become creatures of habit: curtains close at the same time, the downstairs lamp goes off at ten, the bedroom light appears five minutes later, and everything becomes dark soon after. That consistency is convenient, but a routine visible from outside can become surprisingly easy to read from outside at night.
You do not need to turn your life upside down. Once or twice a week, vary a harmless part of the sequence. Read in another room. Close the front curtains a little earlier. Leave one downstairs lamp on longer while you make tea. The goal is to stop your house broadcasting a timetable to anyone who watches it for days.
For an older person, this should never mean changing medication times, sleep routines, or anything affecting health and balance. Keep the important parts of your day consistent. Only vary visible, low-risk details. This is why timers that switch everything on and off at precisely the same minute can look artificial. A real household is slightly untidy in its timing, and that unpredictability can work in your favor.