I think that a mobile phone can be practical since it allows kids to call their parents, but at a young age it could be better to have a more basic phone without internet. This would prevent them from spending all their time on their phones playing games, which could have a negative effect on them. Especially at a young age I think it would be very bad for them to spend all their time on the phone instead of doing sports, schoolwork or meeting up with their friends. A big problem is the fact that there are always young kids with smartphones and this will make other kids also want phones in order to fit in. However, a phone is not necessary in order to fit in and I think it is important for kids to learn not to care too much about what others think. So I think the appropriate age is around 12 years depending on the kid.