In the 1997 movie, Contact, starring Jodie Foster, there is a line in the movie that I always think about when it comes to manufacturing a product; [Spoiler Alert] “First rule in government spending: why build one when you can have two at twice the price?” It’s meant as a jab at frivolous government spending but I believe the government was right to buy themselves some redundancy. I’m sure the fictional government in this movie weighed the risks of spending twice the amount of money to build a second alien space-time travel machine. The point is, redundancy, failsafes, backups, testing, and double-checking are critical when manufacturing hundreds, thousands, or millions of a product that you’ve put some much time into to get a quality, working product in your customer’s hands.