I certainly couldn't take pictures with a phone I just got in my hand. That skill must be handy for John as he gets asked for a picture so often!

I guess he just wanted to see what it looks like, and the 50th birthday seemed like a good date.
Yeah.

Sooner or later he won't have a choice, having dyed the hair for so long it is pretty destroyed.
I don't know much about dyed hair, but if you cut it and regrow, is it still weaker?

It just was all of a sudden. I saw Richard Dean Anderson go grey over ten years of Stargate, and it was a natural process.
It was the same with hugh Laurie in House - you barely notice it if it happens gradually and naturally.