Effects of having a cell phone, it can help you find where you need to go, however cellphones can get pretty costy. An average cell phone bill is around 45$ a month, (prepaid)
You could get lost if you don't have a gps, and if you didn't have a cell you couldn't contact anyone for help. Also if your mo says you have a doctors appt. and you don't know it could be hard for her to reach you and tell you.