My husband likes to keep his eyeglasses on a cord around his neck, so that they are handy when he wants to use them. He only needs them for reading and some other close work, so he doesn't wear them constantly. He has gone through several eyewear cords already, but when he needs a new cord for his glasses, he usually purchases Croakies Eyewear Cords at Walmart Vision Center.
Croakies cords hold up pretty well, usually lasting one to two years (at least, that's how long they last for my husband). These cords are made of woven material, and they fit all types of frames. The only problem my husband has had with these cords is that the rubber piece that fits over the eyeglass ear piece will sometimes split and break. That's when it's time to get a new cord.
For $2.83, these cords are an inexpensive way to keep your glasses handy around your neck, so that they are always ready for you to wear when needed. Hubby seems to like them and keeps purchasing the same kind of cord whenever he needs a replacement, so I would say he is relatively content with the amount of wear he gets out of each cord.
This cord is specifically called the Terra Spec-Cord, and they come in either adjustable or non-adjustable. My husband uses the non-adjustable kind. This is something to consider if you wear glasses but do not need them all the time and would just like to keep them handy around your neck.