Very little. In this case, a single inspection (assuming all units were affected) over a period of 20 years would have prevented losses that more than compensate the effort of the added scrutiny.

Also, I like to be the first to know I'm wrong. If I make 100 aircraft and dedicate one to disassembly for study after a quarter of its estimated life, I'll be a .75% investment on better understanding my product. If De Havilland had done that, the stress on the square windows of the Comet would have been discovered before they started falling from the skies and we'd all be flying more beautiful planes.

I was shocked when I found out that, in more than 100 flights, nobody inspected the underside or the leading edges of the shuttle in orbit to check for damage incurred on lift off. They were pretty sure the only dangerous part of the flight was the re-entry.

You say a problem does not exist. You may have good reason to think it doesn't, and, yet, people die because it does.

You should.

You absolutely should spend time looking for things you expect not to find, because sometimes you will be wrong.

When you're maintaining an aircraft, a nuclear plant, or anything sufficiently complex or life critical, you should spend a certain amount of time looking for ghosts. You _will_ find them. Your model of an engineered system should include a finite rate of unknown bugs.