When I think about reusability in e-learning, I think about objects and content that can be reused in a variety of contexts. Developers often run into this when working on large projects or in industries that involve trade-specific content. When working on multiple projects within one sector, you may come across assets used previously in one course (for example, a 3D model of an aircraft) that may be reused in another course with the same content base.
Being able to reuse content and/or assets can come in handy as it can save you resources in the long run. Reusing previously established assets (if permitted to do so, of course) would reduce the amount of development time various departments and/or individuals need to spend.
Best practices for reusability might include creating your own content repository and defining a file naming convention that will make it easy for you to quickly find what you're looking for. If you're extra savvy, you can create a metadata-coded database, but that might require a lot more effort than you have available.
While it does take extra time to either come up with a file naming convention or apply metadata tagging to all assets within your repository, the goal is to make your life easier in the long run. Much like the dreaded administrative tasks required of small business owners, it's not the most sought-after task, but it's a necessary one, especially if you truly want to optimize efficiency!
Within Articulate Storyline, you may want to maintain a repository of themes and interactions so you can use elements of these assets for future development and save yourself a lot of time. Most projects, in the early stages, require an initial prototype for the client to sign off on the general look and feel. In this prototyping phase, having a repository of themes and interactions can really make the process a lot smoother because you can call on previous work in order to easily facilitate the elemental design of a new project.
Storyline allows you to import content from many sources (for example, PowerPoint, Articulate Engage, Articulate Quizmaker, and more), so don't feel limited to just reusing Storyline interactions and/or themes. Just structure your repository in an organized manner and you will be able to easily locate the files and file types that you're looking to use at a later date.
Another great thing Articulate Storyline is good for when it comes to reusability is question banks! Most courses contain questions, knowledge checks, assessments, or whatever you want to call them, but all too seldom do people think about compiling these questions in one neat area for reuse later on. Instead, people often add new question slides, add the question, and go on their merry development way. If you're one of those people, you need to STOP. Your life will be entirely changed by the concept of question banks–if not entirely, at least a little bit, or at least the part of your life that dabbles in development will be changed in some small way.
Question banks allow you to create a bank of questions (who would have thought) and call on these questions at any time to place within your story–reusability at its finest, at least in Storyline.