If you're having to re-verify the integrity of your game, I'd be concerned about your storage device. Re-verifying also doesn't mean redownloading unless it needs to retrieve new files to replace ones that are missing or corrupt. Updates are annoyingly common as well, and I'd agree that it would be very nice to be able to just say "nah, I'm good" when it's a single player experience. Unfortunately Valve seems to have waived that feature, instead opting to let developers choose how those updates are made available.
I definitely sympathize with those who have data caps. Those are effectively dead and gone in my part of the world, but I can't imagine trying to traverse today's triple-A gaming landscape otherwise.