A notable historical example was NASA's "all-up" decision to launch all stages of the Saturn V on the first test: https://appel.nasa.gov/2010/02/25/ao_1-7_f_snapshot-html/

“In retrospect it is clear that without all-up testing the first manned lunar landing could not have taken place as early as 1969,” von Braun wrote. “It sounded reckless, but George Mueller’s reasoning was impeccable.”