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Let's assume I soldered the right pad with the iron in my right hand. To solder the left pad, I could turn the board 180 degrees so that the unsoldered pad is now on the right, and solder that with my right hand like normal. And this works most of the time. But I've found that when I'm soldering under a microscope, rotating the board throws me out of the loop because I then have to reposition the board under the lens, which takes time if I have to keep doing it. I could also try to solder the left pad without a rotation, but that results in an awkward position for my right hand.
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