I realise have changed my usage-patterns somewhat from N9 days;
I do not use the power button anymore, ever. (Well, yeah, for cycling the power on the device, obviously, but how often you need to do that?? for example my uptime is 9 days now...)

I always lock the device by swipe from the ceiling, and always open it up with doubletap. On N9 I lived with constant fear of my PWR button giving up the ghost, as had happened to many people so this is really a welkome relief