(1) What is device storage? I have 1.3gb being used and 660mb+ free. (2) What is USB storage? I have 12gb total and 8gb free. (3) Is there anything I can do to free up device storage? (4) Also...same theme (maybe?)...what is data usage and why am I getting a 50gb warning? I hardly use this device except as a phone and for taking photos & uploading them to Google drive. If it is related, I am supposed to have unlimited text and data with my plan. So I am confused about the data usage warning. Sorry for the many questions...answers to (1), (2), (3) or (4) individually or all at once equally appreciated.