Porch light on or off?

Growing up, the porch light was turned on at dark and it remained on all night. 

It's something I've continued through adulthood.

Tonight I walked with the dogs to a friend's house about a mile away on the same street. It was around 11 on our return trip, and I noticed nearly an entire block of houses all had their porch lights off. A couple houses had security lights that kicked on. It was a really dark walk. 

As I approached the first intersection, I looked down the cross streets and noticed that illuminated porches were sporadic on each side.

On the block I live, nearly every house has its porch light on. It's just enough light to see out to the street, yet it's not too overpowering. 

I wonder if some of these residents turn on the porch light until they go to bed, and then turn it off? 

I prefer the light on. It gives me a sense of security even though I just realized I'm illuminating my car, so now I have to remember to always remove valuables. It's also easier for the pizza delivery driver to see the address above my garage. 

Is there a standard practice for porch light etiquette? Is it a regional thing? Love to hear what you think in the comments.

Now I'm going to investigate this way too much for far too long.