When you start with a template, how much actually gets rewritten before it's production-ready?

I want to get a realistic picture of template-based implementations. Our team is considering using templates for email nurturing and support ticket triage, but I’m concerned about the gap between “template available” and “actually solves our problem.”

From what I’ve seen in other platforms, templates are built around assumptions that often don’t match your data structures, business logic, or integration points. So you start with a template, customize it, test it, discover it doesn’t handle your edge cases, and end up rewriting significant portions anyway.

I’m trying to understand whether templates genuinely accelerate time-to-ROI or just compress the work into a different timeline. Like, if a template saves 30% of development time but requires 40% rework during testing, are you actually gaining anything?

What I really want to know is: when you’ve used templates in actual production, what percentage of the template code or logic actually made it unchanged into your final workflow? Did templates save you meaningful time, or did they just give you a starting point that you completely restructured anyway?