This can't be stated often enough. Society, diet, education and technology changes, but we've biologically had the same makeup for thousands of, if not more, years.

Just because they're dead doesn't mean they were idiots. This is the young person's folly.

Then again, this attitude may be a substantial cause of what we define as progress. Gray areas are hard to figure out.

Many things in the world are radically different, and the economy especially is a different beast. The point about avoiding debt for example, is hardly relevant for businesses (even if it's generally good advice for personal debts.