As I noted in the comments from the last post, we sometimes get away from talking about basic concepts that I might take for granted. So let's do that.
Let's talk about double-hooking.Double-hooking is the act of using your PCs to NPC for one another. That's pretty much it. Nothing complicated to it.
Pros:This greatly reduces the need for NPCs, and when utilized at proper times, gives the ability for overwhelming numbers of monsters against a smaller group of PCs. It let's you focus your time on guiding full time NPCs into more advanced roles. Finally, it lets you run stuff faster than if your NPCs had to change costumes when running multiple modules.
Cons:NPC shifts break immersion, so doing so in the middle of an important story can be bad. There is less time to guide the NPCs when they're double-hooking, so you might not get the results that you had planned for the module. Also, in costume heavy games, it's a pain for players to change into NPC cosutmes. Finally, you shouldn't require it, because players want to PC. And if you don't require it, you might not get the NPCs you'd hope to have for a specific module.
Have any questions about double hooking? Drop them in the comments!