It took Fred three months to build his first model, needless to say he didn't get lot of sleep during those periods. The second model, Fred started, though a different business, large parts of the model required the exact same logic as his previous one, and same for the third one. Should there be a universal template which consists of all the logics he needs very frequently?

This might not be the exhaustive post, which can guide you on how to optimize excel workbooks, I'm sharing some major findings which I recently came across while working on 200 MB size Excel based financial model.

A financial model is a tool to put theories/predictions to test, a financial simulation to measure suitability of a transaction or a reporting tool to get insights into business performance.