Newer cars have Fobs to lock/unlock AND a alarm mode (headlights flash and horn sounds). If someone does break into your house you can activate your vehicle alarm (assuming your vehicle isn't parked in bed with you). Alarm could scare the intruder away without reveling your location.
When the wife is home every light is on to keep the scary unknowns in her imagination away.
When we are not at home, lights are off. Once it a great while I'll leave a different single light on.
When I'm home alone any light that could be seen from outside is off, I don't answer the door or answer the phone. An intruder(s) assuming "no lights" and "no answer" when I'm home alone would at the very least have to change his/hers drawers.
Once a month wife hosts a week long "party" (Monday, Tuesday, Thursday, Friday & Saturday) to sell "product". Wednesday night church was canceled and I heard voices upstairs. I assumed that since church had been canceled she included this Wednesday in her party. About an hour later I thought those women folks are awfully quite so I went up stairs to investigate. Unfortunately the police are not allowed to profile suspects, I can. Let's just say there was a male "one-eyed purple people eater" sitting in my living room. There are zero "one-eyed purple people eaters" that live in my part of the world so it was obvious to me the male didn't belong. Wife introduces me, he was a sweeper salesman and after giving my wife a sales pitch he was awaiting for his boss to pick him up. I suggested that he leave now and wait for his boss at the end of the lane. As I walked him towards the door our door bell sounded. I open the door to found #2 "one-eyed purple people eater" smiling at me. Before #2 could say anything I told them both that we are NOT interested and they are both leaving now. At no time did I turn my back on either of them or allow the wife to get between them and me. I locked the door behind them and the wife decided now wasn't a good time to explain to me the why. I went back down stairs to finish the project I had been working on and to let my blood pressure go back down to normal. She had opened the door because the door bell had sounded and to see who it was (I pointed out AGAIN that is why we have a peep hole in the doors and that you DON'T open the doors to strangers). When he explained what he was selling wife didn't want to be rude so she invited him in. On hindsight she doesn't think it was a good idea to let him upstairs in our bedroom for the demo!?!?!?!?!? I calmly explained that now a stranger knows what type of alarm system we have (or don't have), the layout of the house and where the master bedroom is and I wouldn't be surprised if the house was burglarized soon. Wife thought it over and now agrees with me that the door between the house and garage should be locked when we aren't home. And yes I was concealed carry during my interaction with both "one-eyed purple people eaters".