Study experts recommend switching between topics instead of just studying one. They say the extra effort of context switching helps you retain and re-apply the knowledge you just studied better than if you just spent a long 3 hour block studying only one subject.
Many CodeCademy classes are already built on this principle, especially the Full Stack Career Path specialization! One lesson discusses the introduction of the internet and the next is teaching HTML tags! Related yet different subjects count as interleaving.
I’m here to get fluent and try to have the meaning of HTML tags and CSS selectors memorized. This is hard to do when I just sit and stare at the same lesson for a long time. So, I’ve been interleaving with alternate study sources outside the platform such as MDN or building a side project from scratch without looking anything up as well as challenging myself with multiple CodeCademy courses at a time.