Most of the private apartments offer the chance of a starter pack of basics like milk, water etc. Its a good idea to take a pack of tea bags, coffee, some sachets of favourite sauces, salt and pepper etc. and some of the small boxes of cereal, not all supermarkets sell small bottles or packs of essentials, we bought a jar of jam last year and used it once, very wasteful, as no one was in the apartment for a few days. Having said that there are always neighbours to pass on any left overs. Another thing we take is a small bottle of washing up liquid, and a couple of sachets of washing machine detergent, just small things, but very useful when you first arrive, especially as we always arrive at night.