Would you let your child buy tobacco once they had enough money? I'm sure there's a certain age where disallowing your child to use a smartphone would be damagi

Would you let your child buy tobacco once they had enough money? I'm sure there's a certain age where disallowing your child to use a smartphone would be damaging to them- but up until maybe even 16 years old - I don't see value in allowing it. I have a much younger brother and I can watch him being mentally harmed from having access to a smartphone. And even worse, the UIs are so simple, the kid doesn't even get computer skills out of it like we did. I myself got some mental illness out of the deal but at least found gainful employment in the process.