The sincere teachers of their youth should be met, not with an intention to dictate to them, but to give additional force to their well-meant endeavours, and raise them to public esteem.
I really like to experiment. That's the only way I can work. It's instinctive.
Trust your gut instinct over spreadsheets. There are too many variables in the real world that you simply can't put into a spreadsheet. Spreadsheets spit out results from your inexact assumptions and give you a false sense of security. In most cases, your heart and gut are still your best guide.