Question: how to know you're being watched?
Answer: A strolling stranger. You probably don't know everyone in your neighbourhood, but a criminal scoping out the area likely won't just look like an innocent walker. ... 
Light bulb problems. ... 
Missing rubbish. ... 
Untouched mail. ... 
A missing dog. ... 
An empty petrol tank. ... 
Social media posts. ... 
A new cleaning person.