As with all things, there is re-use available everywhere. As some of the topics that I cover in various venues become more regular towards education; I want to have both a location for people to reference materials, as well as a location to iterate on previous material as I learn something new.
I use marp as a tool for writing presentations in markdown and converting them to standard slide formats for use through export.
I will make attempts to write material in ways that it can be re-used. Some of these may be catered to very specific focuses and have very specific demonstrations commented.