Negatives
The only reason to have the negatives is for safekeeping. They are copyrighted and you are not permitted to make pictures from the negatives without the permission of the photographer/studio. And even so, since the negatives are likely from professional film, you need to find a professional lab and likely pay a decent amount for them anyway (if the question is about saving money.) I've also found that very few people make up enlargements after the albums and extras are all done. It IS a good thing to have for safekeeping, but I wouldn't consider it a big reason to hire one photograpjher over another.
