We've got plenty to worry about on this here Earth, so why care about the machinations of a planet we've never seen, a few million light years away?
Well, because astrologers believe it can actually help plan our lives in the here and now. Mercury Retrograde affects all signs, regardless of the phase it's moving through during a particular retrograde.
Mercury Retrograde is a pesky type of energy: Under its influence, technology goes haywire, transportation issues crop up, and astrologers would advise you never to undertake, well, any big undertaking (including signing a lease, launching a project or accepting a new job under its influence.) On the other hand, it's a great time to regroup, reflect, and reboot. You'll notice a leitmotif there: any word involving the word "re" is generally safe game during Mercury Rx.
Just Google "mercury retrograde," and you'll see more detailed explanations of what a retrograde period is about from astrologers worldwide. But there's one other Mercury caveat they don't often warn you about: Mercury Rx is also a time when people from your past re—see?—appear. So don't be surprised if a guy who once tempted you catapults his way back into your inbox. What you decide to do with him is up to you.
For more advice on that?Read: Is Having Sex With Your Ex OK?