There was this debate during the 777 development about doors - having a potential weak spot and either being redesigned to include a re-inforcing plate internally - or to wait, tell the end user to inspect the outside periodically for cracking and then face the prospect of fitting the plate externally with the concomitant delays and additional parasitic drag, etc.
In the end they just got on and redesigned the damn door to be stronger in the first place.