Firstly, I couldn't imagine living without my mobile phone. I always carry it with me. I use it in many aspects of real life, but mainly to keep in touch with my friends, even with my parents too, so they can always find out where I am!
Another thing I couldn't imagine living without are my headphones. I am really keen on music. I listen to music very often during the day. I use my headphones when I want to listen to music with the volume as high as possible, so that I don't bother anybody and I don't listen to anybody, either.
The third thing are my glasses, although I only use them when I am in class or studying. If I hadn't them during exam time, I wouldn't study well. My eyes wouldn't be very happy, either!