As a Burglary Detective I can give you some realistic, inexpensive advise.
Layer your defenses like a military position.
1. Your outer perimeter should make your place look less inviting. Fence and locked gate for rural property. Good lighting for suburban property. Motion sensor lights, dusk to dawn lights, etc.
2. The inner perimeter should be capable of considerably slowing an intruder day and night. Good locks including double cylinder dead bolts (they take a key to get in or out) so the BG cannot simply break a window, reach inside and unlock the door. Check with local fire codes as they are not legal in some municipalities. The lock is only as good as the frame it throws into. Use 3" long deck screws to secure the striker plates (the brass plates on the frame the dead bolt/door latch go into). They can kick open the door but they had better be really big and strong and will have to kick it multiple times.
Auxiliary locks on the windows. A good trick is to drill a hole on each side of the window frame slightly larger than the diameter of a double headed nail. Slide nail into the hole (paint nail head to match the frame). This will significantly slow the intruder yet allow easy opening when YOU choose. If a piece of glass gets broken replace with Lexan (polycarbonate) You can beat this stuff with a hammer and it will not break and does not yellow like plexi-glass does.
3. Dogs are good. Large, protective hungry dogs are better. Yappers wake up the eaters.
4. Good marksmanship with a major power firearm. 12ga preferred. The resolve to use it is essential.
5. Cell phone to call 911 prior to shooting and an attorney's phone number on speed dial for after the shooting. Remember this "I was in fear for my life and the lives of my family. I want to speak to my lawyer." Then shut up.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball