Having grown up with Mercury, alias Hermes, I have a thing or two to say about him. He's good at what he does: messaging; trade; dealing with the dead; he's been known to "locate" things from time to time, etc., but he is annoying. He's patron to liars, thieves, and gamblers. He ratted out Circe. As a liquid, he's toxic. We all know someone like him.
Because he's the rascal step brother who's always into mischief, my sisters and I roll our eyes when he shows up. Things go missing and show up later (remember Apollo's cows?) and he generally wreaks havoc and leaves a chaotic trail behind him that we have to clear after he finally leaves.
What happens a few times a year is this: Since he is closest to the sun, his orbit is faster than earth's. That means earth has to stare at his ass a few times a year, and that throws some humans into a frenzy. When his back is turned, he goes on vacation and doesn't bother to check his messages. Communication goes a wonky, people get grumpy, and stuff mysteriously goes missing or breaks down.
To avoid all the hassle that goes along with Mercury in retrograde, do what you would do if a relative you don't completely trust is coming to stay with you for a few weeks. Back up your computer. Lock up valuables. Unplug the toaster. Double check your work. Plan for extra time to get anything done, and go with the flow because he's unpredictable.
The good thing is that always know well in advance of his arrival and departure, so we have time to prepare. This summer he arrives around midnight on July 25 and stays through August 19. Although he's annoying, he does remind us to manage our affairs so we aren't caught off guard if disaster strikes. The good part is that he sometimes gets us out of work. Like a fire drill.