I got my first and only pair of glasses my senior year of highschool so its been about 7 years. I cant really remember what they were like when I first got them but now it seems like they don't work as well as they did back then. I just don't know how I could possibly pick a new pair of frames to wear for the next 6 years.
You will want to get an eye exam every year as good practice and the doctor will tell you if your eyesight has degraded enough since the last time that you will need to get a stronger prescription. Might go years without needing them then go a couple in a row where you need them when you get older.
Also, you don't need to new frames if you don't want. Most places will let you use your old ones and just use new glass if they mean that much to you.