Well, generally speaking, 3d glasses can be reused, and it is safe to do that, so you do not need to worry about it at all. And you also should know that 3d glasses are designed for your eyes to achieve seeing a slightly different image, in which your brain then combines into a three dimensional picture. In common, different 3D displays achieve this in different ways. Nowadays, it is normal to wear 3d glasses when you watch some movie. If you have a pair of 3d glasses while watching 3d movie, it will make you feel that you are just in the real phenomenon. This can be attractive and amazing. And you do not need change your 3d glasses every time.