My family's defense system in the hood was Rottweilers.
When I moved into my own place, I always asked for the apartment on the highest floor and then posted several "beware of dogs" stickers and posters on front door and visible windows. I have two little dogs, not rotts, but they bark enough to keep the illusion up.
I got renters insurance, but when I go on trips, I'll put my expensive things in my safe and hide the good artwork in the kitchen pantry. I keep a light and the radio on at a moderate volume while I'm gone.