I not only left a list but since I had a dog on medication I wrote on the bottles. On the other hand I've heard the story when my Dad was about 18, my grandparents took my uncles and went on vacation. My grandmother wrote down "all" the things my Dad had to do. (feed the dog, water plants, etc) My grand parents came home and all the fish were dead because my grandmother forgot to put "feed the fish" on the list.

So my feeling is leave the list, underline everything if you want. Another thing is leave a note stating that in case of an emergency your sitter has permission to get your babies treated. Probably won't need it but better safe than sorry.