Over the years I have added more glasses to my supply. For years I carried pair of Polaroids and my regular glasses.  The Polaroids are great for seeing the bottom while taxing and for fishing but cause problems reading some GPS screens. To offset this I carry a set with an Airwear lens with gray tint on a polycarbonate lens with UV and scratch protection. These are the ones I wear most often. I also discovered that most of the shooters at my local range were using a bronze glow polycarb lens on over cast days to increase contrast, try a pair they make a huge difference in low light situations.  These are shown in the lower right corner. Color code your holders.