I recently had to get a new phone because they shut down the old analog network. I kept the same carrier, the same account, the same number and the same plan. I pay $8 a month. My new phone is "SIM-unlocked", which means I can pull the SIM card and go to a different carrier any time I want. I don't plan to do that but it's nice to know I can if I want to.
I keep track of my work hours on my phone. I have a shopping list on my phone but I never remember to put anything on it. I read books on my phone.
I still don't know what Instagram is.