I am of the mind, that if someone really wants to rob you.. they will find a way.
So I try to be active in watching what is going on around my property. Security camera with monitor in my office and a few motion detectors. Dogs that bark (a lot). NO ONE, especially the police and the people that work for my neighbors, come past the gate and I do not open it unless I know the person. I make it a point to go out and look at anyone hanging around in the eye and take photos, annoying some that don't return. I have the glass shards on most of the wall and plants with nasty stickers in certain areas. Everything outside is put away or locked down. I keep several security lights on at night and the front gate is opened/closed with the hand held button, not having to get out of the car at night or having to approch the gate to open, leaving a distance from a person that I do not know. Live in caretaker (that can sleep thru anything) Door bolts that require a key to lock/unlock, not only on the entry doors but some of the inside ones too. Bedrooms and office on the second floor, a locked iron gate on the stairs at night. (We do have an emergency escape plan if needed.) I do not have bars on my windows, I don't like to have that live in prison feeling, but have thick safety type glass (and double glass at some windows/doors) that is difficult to break and takes a lot of time and more noise to get thru.
I can not stop the determined thief, I do let them know that I am watching, slow them down, make them make noise and provide more time for me to hit the alarms, house and car.....and get my gun. (That I have let everyone know I have.) And yes, our main house construction materials have been stolen while we lived in an apt. in front of the property. .. was three of the neighbors live in people that learned our habits and how to get over the wall.
Good luck, Ringo