1. The Pareto Principle _ Using spreadsheet tracking, you can easily apply the Pareto principle in deciding which of your income sources and expense channels(i.e. products and services sales) to focus on in order to maximize profits. Considering that you are most likely to use the same marketing/sales resources to serve your customers, it only follows that if you focus on your biggest margin selling products/services, you will get increased profits at more or less the same cost.
You can choose to learn how to do it yourself _ or call in someone(an Excel VB Solutions Developer for instance) who knows how. Again, this would be dependent on your purpose, how proficient you are, and/or how much time you have at your disposal. Ultimately, even if someone develops a custom application for you, it should happen with YOUR guidance at every point to ensure that it does EXACTLY what you want it to do, and that you can easily _ with your developer's support/coaching _ learn how to make modifications to it in future, without needing to call back your developer.
A person with proven competence in this area CAN become "notorious" for developing spreadsheet applications, which eliminate drudgery from the process of using MS Excel to handle large amounts of data. Typically, work that takes hours or days will suddenly take minutes or seconds to finish.
It's not enough to have a professional with the technical skills to solve your problem. s/he also needs to have the right attitude and background/experience _ else the relationship will not work. This is where an Excel VB resource is more likely to add value to you. Most Excel VB Developers have backgrounds in management, accounting, engineering and other fields, which further equips them to be useful to you in "thinking up" better ways to apply your spreadsheet automation to get the most value for your business. You therefore need to choose the right developer, with the appropriate background to match your needs.