How to know when you should change what is taught during a lab classes I teach a lab class that is only constrained by some broad learning objectives. I have been using the same project now for 5 years. It now runs very smoothly and I know what difficulties the students are likely to have. I think that is an advantage, but teaching the class is beginning to feel stale and I am worried that hurts the students. Given I could easily chose a brand new project and still deliver the learning objectives, how do I know when it is the right time to change topics.
The interesting question is, does the project feel stale for you or for the students? The students are, after all, only doing the project once, so there is in principle no harm in using the same project year after year.

Of course, there is the possibility that the project that was cutting-edge when you defined it is now an old relic, using methods and technologies that nobody actually cares about anymore. In this case, you should of course move on, but if this is not the case, I see no inherent value in changing the project (especially since any change also means that the first iteration of the new project will be a bit rough around the edges).