The defensive firearms community has paid some lip service to the “run to the store gun” or “grab a gallon of milk gun” gun, but the issue I take with that is going to such places is by no means low on the risk profile. There is a reason that gas stations are called “stop and robs.” I would suggest that carrying your primary gun to such places is wise.
Where a small and easily wearable gun certainly shines, however, is for home carry, or forays to the outside of the home, such as going to your mailbox. Yes, you can get robbed or assaulted on your way to your mailbox, it has happened more than once.
For such use I find the small-frame snub revolver, combined with a clipless holster such as a Remora or Sticky, imminently useful. The gun can be carried in the pocket or the waistband, and can be put there instantly.
Small pocket autos like the 380acp offerings, or even the larger but still small micro 9mm pistols, can also serve this role. The revolver, however, has a lot going for it as the mailbox gun. The safety provided by the double-action trigger makes it ideal for pocket carry or even in the waistband when used with a Sticky holster.
Having a mailbox gun is a must. I urge people to simply home carry so that one can remain armed at all times. Wearing a full-size handgun all evening long when at home, however, can be a chore. Downsizing to something small and worn in a comfortable way is a better option than having no gun on your person. Likewise, if you must strap on your full-size gun just to walk to the mailbox, you probably won’t. But stick a snub in your pocket? You likely will.
Do you have a small, light, and easily donned handgun for going to the mailbox, doing yard work, or just plain old home carry? You should.