Yes and no. Acceptable failure level is important. It matters if you care about 1, 2, or 10 out of the 30 people on the trip missing a flight, getting lost, or

Yes and no. Acceptable failure level is important. It matters if you care about 1, 2, or 10 out of the 30 people on the trip missing a flight, getting lost, or going hungry. Of course there's a bare minimum for a product that works at all. Beyond that there are increasing levels of rigor that focus on reliability, and these can be non-linear.