slow cooker size and portions question.

[everpuzzled]

Am about to purchase a slow cooker and was going to buy a 3.5 litre one for our family of 5 but just read on Asda website that it'll only feed 2-3 people. Do I need a 6.5 litre one?

We're a family of 5, and I've got the 6.5 litre Argos one, it's a good size for us.