[datavirtue]

Make sure you build subs (functions/methods) for everything....I mean everything. Break all of your code into the smallest subs possible with clear names. Otherwise you will not be able to make heads or tails of your own code in a few months. I built a fairly sophisticated VBA project and left it for a few months, came back and was pulling my hair out. I had to refactor before I could move on, and it was very painful. After the refactor I could make changes and modify it without issue. You have to be, what seems like, over-granular. Its just "clean code" principles: the name of the sub should describe exactly what it does. If the name is too big...break stuff out into different subs.

Excel is perfect for building proof-of-concept apps and Microsoft has a cloud offering called PowerApps that use a somewhat similar "Excel concept." I have built a significant app in PowerApps...not recommended. If you don't have a development team Excel is good. Same for PowerApps. Very painful if they get big. Keep things simple.