Most of the time when mailing to households we recommend using a targeted mailing list with demographics like age, income, homeowners, kids in household, etc. – that way you are reaching the best possible prospects.
That being said there are times when a saturation mailing to all households is a better approach because you are able to save money on the postage. A saturation mailing is where you sent a postcard to all households within an area (no demographic selections) and for some companies doing this will produce the same results as a targeted list. The postage savings is about $60 for every 1000 postcards you send out. Industries this type of list works great for are dentists, restaurants, pest control, auto repair or any business that caters to all demographics.