I can give you a classic case of how location affects defense guns, especially shotguns, and how they change to meet the threat.
What you have to do is make a "Real World" assessment of what the MOST LIKELY threat would be, and set up the gun to meet that threat.
In other words, if you live across the street from a biker bar who are known for assaulting neighbors you'd have one set up, and if you live next door to the police station you'd have another.
About 10 years ago I lived in a house in another small town.
My shotgun was a Remington 870P Police model with an 18" barrel, factory rifle sights, and a synthetic stock.
The local situation was as follows:
The police station was literally in eye sight, about 1 1/2 blocks away.
There was a street light that lite the front yard very well, the back yard was dark but almost inaccessible.
There were close neighbors on both sides, a steep hill with a church in back.
If trouble came they would walk up to the house, and probably would be one or two at most. At the first sign of resistance, they'd almost certainly run.
Police would be there in 60 seconds.
The gun was box-stock with the 4 round magazine. The ammo was #1 buckshot, no light was needed.
Due to the effort needed to maintain a house, we decided to move to an apartment in another larger town, but until the apartment was ready we moved out to the country to a trailer to wait.
The situation was:
The trailer was at least 1 mile from the nearest neighbor, and 10 miles to town.
The sheriff and Highway Patrol were at least 30 minutes away, so an extended gun fight with no help coming in time would make plenty of extra ammo a necessity.
There was NO light, and it's DARK in the country.
It was at the end of a dead-end road, about 1/2 mile off the highway.
Trouble would come in a car, and would likely be 2 or more people since there was a problem with car loads of criminals raiding farms to steal while they thought no one was around. The word hadn't got out that people were now living there.
The gun was changed to a magazine extension holding 6 rounds. A butt cuff holding extra ammo was added, and a canvas bag holding more ammo was with the gun.
A light was added to the gun and a flashlight and extra cell phone was in the ammo bag.
The gun was "Dutch loaded" with the first rounds being #1 buckshot, followed by 00 buckshot, with slugs last.
The idea was a confrontation would take place with the trouble outside their car, so the #1 would start off for the short range.
As they fled away to the car, the 00 would give extra range and penetration of the car.
As they took cover in or behind the car, the slugs would give long range accuracy and penetration of cover.
After a few months the apartment was ready and the situation changed again.
The situation:
The apartment is in an area with various handicapped schools, county health offices, city sports fields, assisted living facility, and a drug rehab center next door.
The entire area is very well lite.
The area starting a block away is the towns "bad" neighborhood with lots of drug activity and gang member wanna-be's engaging in various types of crime, usually not extremely violent, but there is some. They tend to stay out of this area.
Trouble will walk up, and will likely be 1 to 2 people. They don't do violent activities in this area, it's mostly burglaries of cars and houses a block or more away. At the first hint of a gun, they usually run.
The only time they stay to fight is in disputes with their fellow young criminals, usually over drugs and that's in their neighborhood.
There are occasionally some "delivery" attempts by buddies to the rear of the drug rehab center, but this is rare.
The police spend a LOT of time in the bad area and respond very fast to calls, usually no more than 2 minutes.
The Remington changed again.
The gun changed back to the 4 shot magazine. Due to the bright lighting in the area no light on the gun is needed. The ammo load was changed to #4 buckshot because of the close buildings and apartments in the area.
Due to the fast police response, close neighbors who watch out for each other and hear any trouble, and the likelihood of trouble to run away at the sight of a gun, no extra ammo was on the gun. It was felt that a light, fast swinging gun was of more utility than a load of extra ammo that wouldn't be needed.
Last, due to some serious shoulder problems, I can't fire a shotgun anymore, so the defense gun is now a older Pre-Bushmaster Quality Parts built AR-15 Carbine with a 30 round magazine, OR an AK-74 rifle loaded with surplus 5.45x39 7N6-PS tumbling bullets, with a variety of .357 and .45 pistols available as needed.
