Are there any strict definitions regarding the difference between caution/security/safety and waste? For example, consider the following scenarios:
"We just finished this. We'd better test it to make sure it actually works."
"We're going live in a week. We'd better re-test this thing to make sure it still works."
"We're going live tomorrow. We'd better re-test this thing."
"I don't think we've actually changed anything, though."
"Are you 100% sure?"
"Then we'd better test it again, to be safe."
"Okay, it passed. Are we done?"
"No, run it one more time to be sure."
"It's possible you made a mistake when testing it. Run it five times, to be completely certain."
Which of these (if any) would be considered as waste? Which as just being cautious/safe? Is there a formal metric for determining such, or is it opinion-based?