How much percentage to add to the cost of the site design if it is adaptive?

Question

Adaptive design

That is, it is clear that all sites now must be adaptive and mobile versions are not needed.
But here's how much to throw percent over for adaptive?) The
question is rhetorical, of course, but I would like to get a percent fork.

Answer 1

Not at all, this is the standard)) How much do you have to pay extra for a cafe to give you food on a clean plate?

Answer 2

Good comparison)) I understand you