The most effective usability improvement I have been part of involved no design work at all. We removed a field.

Where the experience actually lives

The field required a reference number that most applicants did not have to hand. Roughly a third abandoned at that point, and a redesign of the form would not have changed it — the problem was that we were asking for something people could not answer. Finding out we could look it up ourselves removed the field, and the abandonment with it.

Before redesigning a screen, ask what would have to be true for the screen not to be needed.

Service design asks that question systematically: what happens before, after and behind the interface. A confirmation email that arrives in nine minutes, a support agent who can see the same screen as the customer, a policy that permits an exception — none of those are interface work, and all of them change the experience more than any layout will.