Hubby's eyeglass frame was damaged by my son so he thought he could just buy a new frame or he coud have a new one based on his current prescription eyeglass. But state law requires to have an eye exam if your prescription has expired and it's good for maximum of two years. Meaning, you need to go back again if you needed to have a new frame or wants a new eyeglass. I remember my friend who's wearing contact lens and she mentioned to me that her prescription expires after a year. She has been wearing contact lens since the age of 15 and now she's 40. She has a vision insurance and wants to shift to another. She's thinking of having her dental and vision insurance from one carrier. Out of curiousity, I asked her why there's a need for a yearly and every two years eye exam. She said that optometrists used to rely on the their sales of eye glasses and contact lenses so they don't release a the patient's prescription so that the patient will buy to them again. But the government intervened by mandating that prescription should be given to patient even they don't ask for it. So, they needed to charge more and do a lot of eye exams for profit that's why prescription has an expiration. Also, there are some health issues that are related to the eyes, even we thought that our current prescription still works on us, there might be other things that can only be seen/detected through eye exam.
That's the reason why my friend got herself a vision insurance because she uses it to the max.