nostr:npub1vqhxl0s8n5sa39hks3nyd4hqhzgtsmtn5qnjd5nsvxv9cpa8zcesgtv3yc we use some hocus pocus to measure this stuff. To go from 90% reliability after 10 years to 99% costs more than going from 60% to 90%. So we evaluate that cost compared to the cost of down time and replacement for each item. If it's safety equipment no cost is considered, we go for maximum reliability (parts with failure rates of parts per million, but if it's something cheep and just used for advertising or of low consequence in the event of failure, we do parts per thousand.