There are a lot of good links and suggestions already here. Adding my thoughts: Wet food should definitely be the main diet of any cat, and as good a quality as you can afford. From the financial standpoint, it most often means fewer vet bills; from the caring standpoint, you want your cat to be as happy and healthy as possible. I feed Blue Buffalo and Soulistic wet foods, available from Petco.com and most other venues, online and physical, that sell cat supplies. I do have bowls of Blue Buffalo chicken formula dry cat food for older cats (my cats are 13 and 16) available, as well as a filtered water fountain and 2 bowls of fresh water changed daily. I use SoPhresh unscented litter (cats prefer sandy substrate and do not like perfumey formulas) in uncovered litterboxes. I scoop 5 times daily. This is like humans prefer for our toileting. Cats are very fastidious and often will not use a dirty litterbox, so if you travel, you may want to consider having 2 or more boxes for when you go away. Hopefully your cat sitter is bonded and very trustworthy, or is a well-known relative, co-worker or friend?