We are shortly to be moving (touch wood) to a new house which, downstairs, has a kitchen diner, living room, study and second reception room which is currently used as a dining table. We are only four - me, DH and two DC, and although we do have visitors who come to stay, and host dinners with friends etc, I don't feel that these happen frequently enough to really justify the use of an entire room for a big table and chairs, when the diner part of the kitchen diner is big enough for a table to seat us every day. I would prefer to use the second reception as another living area or a playroom etc. We home educate so I am also quite tempted to use it as a homeschool room to keep the main living room free of "school" stuff.
If you have a dining room do you use it much?