Do you turn off phone on a flight because you are told to?

[Pistom]

In discussion with a friend yesterday, this came up in discussion and I realised that it's something I give little thought to.

I turn mine off to conserve battery on occasions but am pretty numb to requests to turn off your phone. No idea why, I just am.

I'm wondering if I'm the exception. He said I was the only one he knows who was so reckless as to do this and I couldn't explain why I don't turn it off.