This TeX.SE thread is a good resource for how to make your usual preamble into a package or document class. I would like to know why I should do that. What are the pros and cons of doing so, as compared with just leaving the preamble in every document you write?
Here's how I see it:
Pros of leaving the preamble in every document
- Easy to edit it if necessary
- If I forget how I defined something, I can just scroll up and look
- Only one file to keep track of per document
- If I send my document to someone else, they can compile it immediately, without any fussing over where to put my package/class file
- Progressive changes to my preamble don't cause an accumulation of files that can never be moved lest all old documents break
Cons of leaving the preamble in every document
- Takes up more room on the computer
- You have to scroll down a bit more before getting to start writing in your document
(the pros and cons of making a package or class being exactly dual)
To me, this comes down heavily against making a package or class. Am I missing considerations that would tip the balance the other way? Perhaps for certain documents, one choice is better than the other?