I live in a 3rd world country and prpepare for 3 situations. First, a non pro intruder trying to rob the house in which case sit still and absolutely quiet until and if intruder is point blank. I keep a Beretta .40 and a surefire light in holsters on the bedrail. Second, a pro group of intruders/attackers entering or attacking to rob or kidnap. In this case a shotgun with buckshot with integral light, start shooting and close distance. I have had several attempted intrusions in the past few years and take this all pretty serious... pre thought lines of fire/attack and extra shells and clips strategically placed throughout home. Third is a non pro outdoors screwing around with my car or looking for petty theft. In this case a harsh warning, sound of shell racking into chamber and surefire light into face. My living space is in the second level and storage and carport on ground level. First level of protection and alert is an australian cattle dog on the balcony at each of the two primary entrances. But for shotgun purchase my opinion is shorter is better and practice until handling and firing is instinctive. If you need to be thinking in the real moment of need, your'e screwed.
If anyone's wondering how to tell the difference between pro's and non pro, here in central america the pros come in hard using shock and surprise.. the non-pros try sneaking around.