The lifespan of plexiglass is determined by how often they are used or what type of environment they're in. The stability of plexiglass also depends on the thickness; acrylic panels that measure over one square meter should have at least four millimeters for safety purposes (though this may vary depending on your needs). Plexiglass lasts longer than other plastics because it doesn't scratch as easily or loses its color like vinyl will do with time.