Videotape or take photos of all valuable possessions. These also should be marked with an engraving pen to help police trace and recover them if stolen. Don't allow strangers into the home to use the phone and never leave service technicians or repairmen alone in the house. These individuals might be casing homes in the neighborhood for possible burglary targets. Never place keys under the doormat, flowerpot or window ledge.
Burglars study the daily habits and routines of people.
Experience has taught them to check these places first when casing a house.