Most of us don't replace our glasses on a schedule. We replace them when something breaks, or when we finally get tired of putting up with them. The trouble is that glasses wear out slowly, and our eyes change just as slowly, so it's easy to live with a "good enough" pair for far too long.

If you're wondering whether yours are past their best, here are five signs worth paying attention to.

1. You're squinting more than you used to

Catching yourself squinting at road signs, restaurant menus, or the TV is one of the most common clues. If you used to read things comfortably and now you're leaning in or narrowing your eyes to make them sharp, your prescription may have shifted since your last pair was made.

Eyes change gradually, so you rarely notice it happening. You just find yourself adjusting around it.

2. Your eyes feel tired or you get headaches

Tired, achy eyes by the end of the day, or a dull headache after reading or screen time, can be a sign your glasses aren't doing their job anymore. Headaches have lots of possible causes, so don't assume it's your glasses. But if the timing lines up with computer work or reading, it's worth looking at.

3. Your lenses are scratched, smudged, or hazy

This one is easy to miss because it creeps up slowly. Tiny scratches scatter light, which can show up as glare around headlights at night or a general "dirty" look that wiping doesn't fix. If you clean your lenses and things still look slightly foggy, the lenses themselves are probably worn.

Once a coating wears off or the surface is scratched, cleaning won't bring it back.

4. The frame doesn't fit like it used to

Frames loosen over time. Maybe they slide down your nose every few minutes, sit crooked, or leave red marks behind your ears. A bent frame also changes where the lens sits in front of your eye, which can make your vision feel slightly off even if the prescription is fine.

A quick adjustment at an optical shop can fix minor looseness. But if the hinges are wobbly or the frame has warped, it's usually better to start fresh.

5. It's been a while since your last eye exam

This is the one people skip. As a general rule, many eye doctors suggest a check-up every one to two years, though your own schedule might be different depending on your age and eye health. If you can't remember your last exam, you're probably due, and a new exam might mean a new prescription too.

Even if your vision feels fine, an eye exam checks more than sharpness, so it's worth keeping up with.

What to do next

If two or three of these sound familiar, start with an eye exam so you know your current prescription. After that, picking a new pair is the fun part. Online shops like Viewner let you take your time with it, so you're not rushing through the decision at a store counter. You can browse a full range of prescription eyeglasses, compare frame shapes and materials, and see what suits you.

And if you're replacing glasses you've worn for years, give yourself a little time to adjust. A new pair, even with a better prescription, can feel slightly strange for the first few days.