When having family or friends over for dinner, especially on special occasions like Easter and Christmas, do you cook all the different dishes yourself, or do you ask those who are coming to bring a dish of some sort? In my part of the world, when people are having big lunches or dinners, they would ask each of the invitees to prepare and bring a special food item. So, even though the hostess of the lunch or dinner would prepare most of the items, those who are invited would bring either a dish of their choice or one which the hostess asks them to bring. It could be either something savory or some kind of dessert. Doing this not only makes it easier for the hostess where the food preparation is concerned, but it is also helpful financially too.
Here if we do something like that, I usually cook all the food because I've got a lot of food allergies and to be honest I don't trust others to prepare food that I can eat. That being said though, I certainly encourage them to bring drinks along. I don't really drink alcohol anyway so it's better that someone else brings that, and they usually bring soft drinks as well. I'll also tell them to bring other things sometimes like paper plates or plastic cups. I usually have loads of those anyway but the more we have the better!
When we have house guests particularly for occasions, we cook our food not really to save. The main reason is because usually the house guest would have a request for that - we cook our specialty dishes that they can only taste in our home. We have pork and beef dishes but our best best and all time favorite is the crabs cooked in coconut milk. But admittedly, cooking food for guests certainly saves from the bigger expenses of catering services.