[MichaelJ]

I do not find that I ever need goggles simply for the cold. I did a hike on a cloudy day to a tree-covered summit and it was -26° up there, and while I exposed very little of my face, using a full balaclava and a hat as well, I did not need goggles. There was no wind at all to speak of, so I just covered everything else up. I was also on Washington in temps between 8 and 15 (I think), but with no wind to speak of I just used sunglasses.

I've also been on the summit of Moosilauke with temps in the teens, but with 15-25mph winds, bright sunny day and no reason not to be up there, but it was necessary to make sure not a single spot of skin was showing, thus the goggles.

And yes, there are places below treeline where they could come in handy if the wind can still reach you through the trees. Along South and Middle Carter comes to mind as one example. My personal feeling is that generally as long as it's not windy and you keep your body warm, keeping just a small part of your face and eyes exposed is going to be fine ... your body will keep plenty of blood flow to that skin and protect it. It's when it's windy out, that 100% protection with goggles becomes necessary. Even with plenty of body heat, you can't keep up with what the wind whips away, and you definitely don't want to risk freezing the corneas of your eyes.