A few years ago, a gangbanger held up (of all things) a clothing store. On his way out, he ordered the clerk not to report the robbery to police. The clerk ignored the order and police found and jailed the robber. If the clerk mentioned the threat at all, I expect police told him not to take it seriously. On orders from the robber, another gangbanger went to the store and shot the clerk.
A law abiding citizen was scheduled to testify against a drug dealer. After receiving death threats from the dealer's associates, he obtained his CCW permit and began carrying.
Both are examples of definite, credible threats that would justify keeping an effective handgun constantly within reach as you go about your daily business. Since the time and place weren't specified, it wouldn't be practical to carry a long gun. (If the time and place were specified, the wise move would be to have police waiting for the assassins while you were safely elsewhere.)