Blurted out during a planning session and presented here for your consideration:
“Consistency is almost never a factor in conversion effectiveness.”
By that I meant that just because a button works on one page, it won’t necessarily be the winning button for another page. Just because a message resonates with one audience, it won’t necessarily be the message that clearly communicates value to another audience.
The one dimension where consistency matters is in communicating benefits across the user experience. If you brought a visitor in on the promise of, say, protecting their kids, don’t change the message a page or two later to be about how little the service costs, unless you’re talking about trading off payment for peace of mind.
Context matters far more than consistency.