Hi Jonathan,
Thanks for a great "3D Modeling Basics" course!
In this course, we built the box as multiple objects.
In real life, we will duplicate the box, scale it, move it, shade it, and so on.
To combine those objects, we can use at least: collections, parenting, and joining.
(Am I missing another grouping method?)
What are the use cases for each of those methods?
BR,
Izack
One other could be collection instancing. That one has the advantage of saving up on your computer resources. I'd say there is no wrong answer, you can use which ever method you prefer, given that is best for any particular situation. Joining meshes is kinda destructive so I'd leave it out of collections and parenting.
I use parenting if I'd wanted to move a ground of objects around. Collections is for your scene organization more than anything.
I don't think you're missing anything!
I use joining if each part can share the same object properties (modifiers, scale, etc.) and I want to easily interact with it as a whole. I'll use parenting if I want to move, rotate, or scale things together but need each piece to have different modifiers or object properties. Collections, like Omar mentioned, I'll use to organize the scene to create instances. I really wouldn't worry about instances just yet - that's mostly for when you have complex combinations of objects and performance is becoming an issue or you're linking collections between blend files.