The Apple Watch screen was supposed to be extremely scratch resistant, so of course I scratched mine almost immediately moving a chest on our brick hearth. In case you wondered who would win between an Apple Watch and brick, it was the brick. To be fair, it’s not noticeable unless the light is just right. Still Hubby decided I needed a screen protector and purchased me the ZAGG InvisibleShield one below from Amazon.
I am always disappointed that screen protectors for any device seem to leave the edges unnecessarily exposed and the ZAGG was no exception. There was a noticeable edge when swiping, but nonetheless, I wore it for several months. I was very pleased with the clarity; there was not any difference to me in brightness or readability. And there were multiple occasions when I marked up the protector, no doubt saving my screen. But the edges started collecting debris and eventually lifting up as you can see in the bottom corner below.
There was also a noticeable debris line all around the edge.
So if you are klutzy like me, it might be a good idea to get a screen protector, but you should expect to replace it much more frequently than you would for a tablet or phone.