Me: "Hello, big boss! I'd like to go to IPv6 soon!"
BB: "What will that take?"
Me: "Oh, probably a couple of months worth of completely dedicated work from your best network folks. If you don't exclusively task them, could take a year."
BB: "Sounds complex. Is it risky?"
Me: "Absolutely! We could totally drop off the internet or lose internal connectivity for quite a while if we mess it up."
BB: "What, exactly, am I getting from this expensive and risky thing?"
Me: "More or less what you have now. The features it does you don't really care about."
BB: "So it's expensive and risky and I get nothing out of it."
Me: "Yep! When can I start?"