The temples, also known sometimes, as the arms are the part of the glasses that will secure the frame front and keep the glasses on the ears.
Temples are usually made via plastic or metal and have a lot of differences between them. That includes differences in strength, flexibility and the reaction your skin will have from them.
Metal temples are usually more robust to breaking and bending compared to plastic. Plastic temples, in contrast are usually lighter. Your choice will usually depend on the activity you are participating in with your glasses.
Usually, when a temple is bent or broken it can be replaced and doesn’t require an entire new pair of glasses.
Spring hinged temples are another option you may want to look at. They offer a wider opening of the temple without it breaking. These are probably beneficial for those with larger heads and faces.
No matter, which type of temple you choose, it’s all about comfort and choosing the frames and temples that feel best on you!