The third child doesn't bathe as often as the others. And all the baths that do happen take place in the kitchen sink.
The third child doesn't change clothes as often. A little spit up stain never hurt anyone, right?
The third child doesn't have a set schedule because, well, let's face it, the second child didn't either.
The third child has to deal with his sisters fighting to hold him.
The third child stays swaddled most of the day because it's the easiest way to keep him calm.
The third child does get the most kisses though, from all four family members that are absolutely obsessed with him. That must make it all worth it.