Keep a copy of your prescription so you can buy glasses online for cheap.

Glasses fog up when you go from cold to warm. Clean the lens with soap water and wipe them off to keep them from fogging up. Or use good ol fashioned spit.

Check the screws and whatnot on the hinges periodically. Sometimes they go loose. Depends on the glasses.

They help keep rain and midges away from your eyes, so that’s nice.

The nosepads get dirty too, so wipe em down every now and then.

If you play sports and you don’t care for contacts, or if you swim, think about getting prescription googles. 100% worth it.

Take them off on the rollercoasters. Put them in your pocket or something.

Buy a spare pair in case of emergencies. This is equivalent to not having a plunger when you need one. You’re gonna regret it!

If they get bent somehow and don’t sit properly on your face anymore, try to avoid bending them back yourself. It’s better to have a professional do it. They know where the stress points are and how to do it right without breaking them!

Be careful when cleaning them, otherwise you’ll get scratches. Even expensive ones. Don’t use those wipes with alcohol, it’ll damage them. Either use soap and water with a clean cloth or sponge and dry by dabbing with kitchen paper. You could also get an ultrasound cleaner, which is like a little bath you just put them in. Don’t wipe them when they are not wet.

Make sure to get a pair that actually fit your head. They shouldn’t squeeze your temples, the ear bends should actually be on your ears, they shouldn’t slide around on your nose.

I wore glasses for like twenty years before I finally realized the source of every single problem I had with them was actually me picking the wrong frames and not inherent issues to glasses. Now that I’m aware of it I notice other people wearing ill-fitting glasses all the time.

Keeping a few of those little lens cleaning cloths in convenient places is about all I can think of. They launder fine too, if you notice any become less effective at removing smears.

If you ever need a new prescription, they should be able to put the new lenses in your current frame. Similarly, if your frame ever gets broken but your lenses are undamaged, they can pop them in a new frame. That said, keeping old glasses as spares is useful, and it can be fun to have new frames.

If you work in an environment where you go from cold to warm and they fog up often, you can get antifog treatments that don’t last forever but do help keep them clear.

Buying a few pairs from cheap online sellers like goggles4u can save you a bunch of money. The antiglare coatings are applied to almost every lens already so don’t bother paying for more coatings.

If you have to wear them constantly, like I do, remember to wipe them down with a gentle soap periodically. The spaces between the frames and the lenses will collect gunk that makes you think something is in your eyes and drive you crazy.

@paris mentioned one online retailer already but to give you another option: I’ve been using Zenni for my prescriptions for a few years now and have been happy with them.

Sometimes a vendor or optometrist isn’t contracted with your vision plan, but you can often submit for reimbursement; some health insurances (since eye health isn’t health, somehow) will also allow you to submit for reimbursement so check your policies, if applicable.

I tend to order two non-tinted pairs and a pair of prescription sunglasses when my Rx changes noticeably - one pair is made of safety polycarbonate (shatter/puncture resistant) and the other is more standard, but it’s nice to have options to choose from. As you go through them, please make sure to donate your old prescriptions! I’ve sent most of mine to the Peninsula Special Interest Lions Club in CA but there are a number of charities that will send your old lenses and frames to people who need them

If you can afford it, get another pair with ‘transition’ lenses that get darker in direct sunlight. Regular glasses are going to make sunlight more powerful; I used to get headaches every summer unless I wore a hat all the time. It’s easier to just have the one set that get darker than to fool around with prescription sunglasses and noraml ones.

There are swimming goggles with prescription lenses available. They cost about the same as normal goggles, and make sports much more enjoyable.

If your prescription is mild, you may be able to get away with using reading glasses from the drug store. Most of the bigger places have a rack where you can try them on.

Pets often enjoy chewing on the glasses, so be sure you put them in a safe place every night.

Lenses scratch over time, plastic ones faster than glass ones. The coatings are the first to go, so you can use that as a warning sign to get a new pair ASAP. Try to keep them in a microfiber lined case or pouch, not just a random shirt pocket.

If you start seeing “starburst” effects around lights at night, it means the lenses most likely are scratched.

Only clean them with a microfiber cloth, and never dry. At the very least, breathe on them to have some moisture. Blow on them first to get rid of any dust that would come off easily. Avoid rubbing dust into them, even with the microfiber cloth. It’s best to use a single motion from one edge to the other, ideally while pulling the cloth away so dirty parts don’t get dragged along the lens (takes a bit of practice). Shake the cloth off after each pass. Goes without saying, but clean hands are required to keep the cloth clean.

If you really have to, you can put them under running water, but beware of corrosion in any metal parts (frame, hinges, screws). Shake off leftover water, then clean with a microfiber cloth. DO NOT use a hairdryer on plastic lenses or frames. Depending on the water hardness, it might leave mineral deposits behind, so it’s generally better to avoid it. Rain is usually fine, unless you get into acid rain, or dusty rain.

Chromatic aberration is inevitable, so no point in fighting it or panicking, it just comes with the territory. With a good pair of glasses, whatever you’re looking at straight ahead, should look fine though. If it doesn’t, consider getting back to your optician for a better fit.

Random reflections and glare are a thing too. There are coatings to mitigate them, which makes sense for like driving at night, but you might get by without them, YMMV.

If you travel by auto when wearing tight clothes be sure to mind the extra clearance needed for your glasses when getting inside! One of my trendy larger frames took a scratch that way soon after getting them. Also don’t limit yourself to just two pairs but instead get some cheap ones to change up your appearance. Accessorize :)

Pay close attention to the fitting, tightness of the nose pads, bends of the arms. Shape all that so they won’t fling off off you look down quickly or if you flick you head to the side.

Also, be aware that they will fog up when you pass from a warm environment to a cool humid one. Or like, when you open an oven or rice cooker.

You can adjust them, but it is better if you get them adjusted wherever you bought them because they know how to do it properly. In particular, the spot where they touch your nose might get sore, and maybe moreso on one side than the other. That’d be a sign to get them adjusted. Some people even have one ear slightly lower than the other, needing an adjustment to the arms.

Glasses have an optimum focal point so your glasses were meant to be a particular distance from your eyes and over adjusting might change that. On the other hand, the change is going to be so small that it probably only matters to the people selling glasses rather than the wearers.

Buy a few cheap pairs online right away. Expensive glasses are not worth the cost.

Zeiss lens wipes are the best, but soap and water work great too. Rubbing a towel on your lens will scratch it eventually.

Your glasses are probably cheaper buying them from LensCrafters on your work insurance, but I discovered Roka and will not go back to others even though it’s more expensive off insurance. Their glasses are so light, comfortable, and stay on my face. I’ve been alternating years, glasses one year sunglasses the next to save money so I can splurge on good frames.

Progressive lenses are hella expensive and become necessary in your 40s. They are nice to have when you need them though.

People have mostly covered the important stuff, so something less important is: if you are liable to take them off with any regularity, you’re gonna lose them on top of your head! I keep mine on pretty much any time I’m awake and not doing something specifically anti glasses (think swimming), but I know especially people who are farsighted while watching TV or nearsighed while reading will do this.