I wrote an include file to allow me to draw certain diagrams (that have various different parameters) conveniently, by just calling macros within a tikzpicture. This file is now at about 1500 lines, although a fair amount of that is notes I wrote (in the form of TeX comments) on the various macros in case I come back later and need to remember quickly how they work. Or I suppose, in case someone else wants to use it.
Anyway, I include this file in the preamble of my document just using the
\input control sequence. But I know that the "standard" way of making reusable code is to create something called a "package". What extra work (if any) is involved in making this include file into a package, and how will I benefit (if at all)?