Myth: never sign anything when Mercury is retrograde

This one comes from Western pop astrology. Classical Jyotish doesn't treat a retrograde transit of Mercury as a reason to freeze.

Retrograde planets are counted strong. A Mercury retrograde can be a good time to revise, re-read and go back over things. Checking the contract twice is sensible any week.

If timing matters to you, the day's golden windows and Mercury's hora are more useful than the retrograde calendar.