Benefits of Good Form
Using good form promotes reusability because the programmer can easily spot code used in the past and then copy and paste portions into new applications. As time moves on, code can mature and be used over through shared workbooks or even creating an add-in. Shared workbooks can simply be a single spreadsheet that contains common modules that can reside in every user's desktop or better on a shared network folder (to ease maintenance). Other applications can call the shared workbook directly to perform the functionality with a simple function call as follows:
Application.Run "'<shared workbook file name>'!<module name>"
Finally, if the code is used frequently and is likely to not change over time, taking the portion of the code and creating an add-in for users to install on their computers is the cleanest and most protected form of reuse. But do not forget to use good form with an add-in, and always save the original code before you compile it into an add-in!
Using good form is a benefit to programmers and not for users, so why not give yourself a break?