At what age should parents give their children cell phones and defend your choice

In my opinion, parents should give their children cell phones when their child is becoming more social and mature. The age would be around 12-14. I believe it's best since while cell phones are great for connecting long distances, there is a lot a naive child shouldn't venture out and do without adult supervision. A 10-year-old doesn't need a cell phone, an active 13-year old would if they go out a lot with friends.