This is a question about best practices and the intent of the designers of SharePoint.
I'm pretty new with SharePoint, and have only worked on pretty small projects. I often find myself creating custom lists and libraries. In this specific instance, I have a document library which my users will use to collaborately edit and verify the contents of a large number of Excel spreadsheets. I have a separate list which, using event handlers, tracks the changes done to elements in the first list.
When I do this kind of work, I usually just create a custom list or custom document library where I use the "Create column" menu option to add columns. I almost never use fields from pre-existing content types. I have occasionally created a custom content type for the entire list, but the entire process just seemed more complicated and maintenance-intensive than it needed to be. However, I'm assuming that there is some issue related to scalability or reusability that I'm not seeing here. Is this even a relevant question to ask?
- Are there any compelling reasons why content types/site columns should be used instead of local, custom list fields?
- Are there any compelling reasons why local, custom list fields should be used instead of content types/site columns?
- Are there any deeper problems than just the duplication of functionality when it comes to, for instance, avoiding to use a standard SharePoint list type and instead create a custom list that stores pretty much the same information?