No offense to our senior riders, but man, your vision must REALLY be shot if a clear Pinlock visor cuts down the light that much. Heck, IME, the *dark smoke* Pinlock visor (their darkest) barely cuts enough light in the sun for me.
Now, I can't ride at night with the Dark Smoke visor in, when I must ride at night I switch out the shield for a blank one (which is a pain, but having one of these handy bags in the frunk solves that problem:
http://www.amazon.com/Simpson-Racin...UTF8&qid=1361668452&sr=8-1&keywords=visor+bag ). But I've never had to switch out the clear Pinlock at any time. Must be all the carrots I ate as a kid. :joke:
Anyway, once I have enough pennies saved up I plan on replacing my Shoei Qwest with the new Shoei GT Air, which comes with an internal sun visor, meaning I can go back to using a clear visor all the time and no swapping out for nighttime.
As for the Pinlock failing... it's a wear item, unfortunately. I've had some visors last an entire riding season; others start to warp just enough to allow condensation in a few months. The key really is to just get a good seal the first time, and then never, ever touch the thing again. (Take your entire shield off the helmet if you need to wipe down the inside-- use the softest cleaning pad you have to wipe down the visor, you're right that they do scratch. But a little spritz of Plexus and an iPod cloth does the trick for me).