As for burglars, theft is the least of my worries. I have insurance.

You really can't "harden" your home to any significant degree. You can make it "better", but you'll never even get up to "good" without spending a ton of money. Bars on all your windows. All steel doors in reenforced frames. Remove skylights. Replace any siding with brick or rock - solid - all the way around. Etc. In other words, turn your house into somewhere you probably wouldn't want to live in the first place.

If someone is intent on a "home invasion", as was the topic of the first post in this thread, you better be ready to detect and repel that.

Reenforce your home to a reasonable degree. Not expecting to "harden" it, but to make it more time consuming to get in. Even slowing someone down for a few seconds will help. Get large dogs as a warning device. Put in an alarm system (if you can afford it). The alarm system would be to alert YOU, not necessarily the authorities. By the time the authorities respond to your alarm, the invasion is probably over and you are already dead.

The only things I care about in an attack on my home are the safety of my family. So if someone breaks in using force, they can expect to be met with overwhelming counter-force. I want my family to survive the encounter. We heavily stack the deck in our favor. If you find yourself in a "fair fight" when someone breaks into your home, your tactics stink.

You will never "keep them all out" if they want to get in. So your plan should be early alert, and tactics (including weapons) that will allow you to survive.

Burglaries when we're not at home? Insurance is the answer for that. Home invasion? $500 door locks will not save you from that. The best you can hope for is a few extra seconds for you to rally your defense. Spend your money with the understanding that you are buying yourself a few extra seconds to respond yourself, not hardening your home to any significant degree.