1. Clean with the right cloth: Only use a clean microfiber cloth and lens spray to wipe your glasses. Shirts, tissues, and paper towels feel soft, but they carry tiny fibers that will scratch your lenses over time. If your glasses are really dusty or gritty, rinse them under lukewarm water first.
2. Case it or wear it: If your glasses aren't on your face, they belong in their case. Tossing them loose into a bag, pocket, or car cup holder is a guarantee for scratched lenses and bent frames.
3. Use both hands: Always take your glasses off using both hands. Pulling them off by one side places uneven pressure on the hinges, stretching the frame out until they start sliding down your nose or sitting crooked.
4. Keep them out of the heat (and don't DIY adjustments): Never leave your glasses in high heat, such as inside a hot car or near a window. Intense heat can warp the frame and permanently ruin the lens coatings. Likewise, if your glasses ever feel loose or crooked, don't try to bend them back into shape yourself. Pop into a local optician instead. Most shops will happily do a quick, professional adjustment for you.