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.
Another question I ask, in answering the "Why Excel VB?" question is : "Why re_invent the wheel? ". My experiences(and those of others who favour the use of Excel VB like I do), confirm that to organise, and analyse data for (financial/management) report generation and decision making, you will save hundreds of hours using already in_built, pre_programmed Excel functions compared to a situation where you used Visual Basic proper. All the functions needed to achieve the above purposes already exist in Excel, so that you don't have to write them all from scratch as would be the case if you were to use Visual Basic. 3.It works even when you lack "In House" expertise.
One Possible Application: Plotting a pie chart based on income contributions from all your products and services(daily, weekly or monthly), and reviewing the automatically computed percentages/visual pie slices, can give very illuminating insight.
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.