I know there is no hard and fast rule on this subject, but I'm trying to feel it out and plan accordingly for my game.
Right now my main sprite collection takes about ten seconds to commit when making changes. I'm about to add a very large boss to the game with a lot of sprites and odd shaped-moving parts. I feel like this will take a large toll on my existing collection. I think it makes sense to put the boss in his own collection because he only appears in one scene of the game, no need to have him loaded at all times.
So that begs the question- should each boss be in their own collection?
Is there any inherent risk to having too many collections altogether?
Right now I have a collection for my tiles, a collection for elements that don't need lighting, and then everything else. I just don't want to go overboard with the collection process. Much akin to how someone new to OOP starts making a class for everything they can think of.