Dad's family never goes grey - but let me tell you, those aunts and uncles that had black hair can look downright scary when they are old and wrinkly!
I'll be 50 in a few months, no greys yet, but ratherthan blond, it's kind of a dark blond/mousy something. It is thinner than it used to be, too. I'm pretty low maintenance, so even if I get greys, I doubt I'll bother iwth coloring. Keep my hair quite short, a quick blow dry in the AM and run some gel through to add some body, that's it.