Your choice of home defense ammo should be tailored to your living accommodations. As a rule of thumb the pattern of a shot column opens up about an inch for every yard of range, heavy shot keeps a tighter pattern than fine shot, and the lower pressure shells tend to pattern tighter than high pressure shells. The larger the pellet, the deeper it penetrates, but penetration is a two edged sword; not enough is bad, but too much might be worse. Start with the premise that you are putting more than an ounce of projectile onto the target, then do some testing to ensure the penetration and performance you get from any given shot size and velocity is the performance you want or need. In addition to all that, two equal loads from 2 different manufacturers will pattern differently, and either one will also pattern differently when fired from different guns. Don't assume that your Remington will pattern the same as your Mossberg, or even the same as your other Remington. Don't assume your Kent shells will pattern the same as your Winchesters, even though the shot size and powder charge is the same. Get out and pattern the ammo you're going to use in the gun(s) you'll use it in.
Take measurements in your home, and replicate those shooting distances on the range so you know what your home defense ammo will do in every conceivable scenario. Household ranges tend to be short, measured in feet rather than yards, and this needs to be considered when appropriate ammo is sought. The dangers of choosing powerful shotgun loads for home defense when living in an urban environment has been covered ad nauseam, but there's nothing like seeing this stuff for yourself. So pick up some scrap dry wall and insulation, a few concrete blocks, and a bit of lumber and shoot at it to see how well your walls stand up and see if your choice of ammo is prudent for the purpose you have in mind or if it poses an unreasonable risk to other family members or neighbors. There isn't much need for a 3" magnum 12 bore in the home defense roll and if 80% of the pattern hits the bad guy, it means that 20% is going into the furniture, walls, floor, or ceiling. Where does it go from there? That depends on the layout of your home. But in a real world shooting scenario, every single projectile out of that gun barrel, be it a pellet or a slug has a lawyer attached to it, and after the action every single one will be accounted for.
If you come to the conclusion that skeet or heavy game loads are the best choice you can use the same ammo for home defense as you do at the skeet range. If your setting is more rural, you might prefer to have high velocity #2s for the house or even buckshot and a few slugs in a sidesaddle should a firefight erupt across the yard. Recoil and muzzle blast are not your friends, and both will numb you and slow your actions. Speed of movement and the ability to respond quickly to a fluid environment is essential. You will load and unload more than you'll shoot. Can you do that in the dark, without seeing the gun, while under stress, without fumbling rounds? Can you transition from shot to a slug or vice versa without tying up the gun. Can you identify different loads without seeing them? Violence will come to you when you least expect it, and probably in poor light. You'll have to fight with the shells that are in or on the gun, you won't have time to go get them. A light on the gun will be useful under these conditions. Your gun, ammo, and cell phone all need to be accessible or they are of no use to you.
