said by Blackbird:
The truth is that if somebody wants to break into an unoccupied home, they can - and they do, daily.
I came to the same conclusion when shopping for new locks when we last moved. I could buy very good locks, but somebody could still get in by smashing a window. I settled for having the existing Schlage locks rekeyed with a custom 6-pin combination from a locksmith that would be difficult to bump. I took the cylinders to the locksmith and had it done for $11 per cylinder which was much cheaper than new locks.
Also every house I've bought had different keys for every door - which drives me crazy.