Advice on buying a food processor

Hi
I have been searching around for a new food processor, and have noticed that among other information they also have the size stated.
I am not sure what the size would mean in practical terms - or in short, if I usually cook for my family of four, and sometimes for guests, what would be a good size?
Help appreciated.

Nobody but yourself could answer that, Eileen. I thought though that food processors came in standard sizes.

Food processors come in all different sizes. There is a standard size but there are also smaller and larger sizes.

I like the bigger size, because we use it to make butter, and generally start with a quart of cream.