If you really want to build a house that fits your life, you first have to decide how you actually live your life in your current home. Forget square footage, forget bedrooms and bathrooms, forget living rooms and family rooms. What you need to know are functional spaces. You need to track your life from the moment you get up to the time you go to bed and do that for every member of your family. You need to account for weekends, guests, parties, and hobbies.
Starting from your morning, where is your bathroom? Do you share your bathroom with others? Do you need a tub? A shower? Just a sink? How many people in your house use bathrooms in the morning at the same time? Where do you store your clothes? How do you put on your shoes? Do you need a chair near where you get dressed? Do you watch television in the morning? Listen to the radio? Do you need coffee before you even get dressed? Do you need to take care of young children first thing in the morning? Are their bedrooms close by? Do you have teenagers? Do you need to roust them from bed? Do you eat breakfast? Do you eat standing at the counter? At the breakfast table? In the dining room? Do you make breakfast for others? Do you pack lunch for others? Do others work in the kitchen at the same time you do? Do you leave the house to work? Where do you leave your keys, your wallet, your purse, your briefcase, your coat? Where does your family leave the things they need to take out for the day? Where do you park your car? How many cars do you own? Or do you use public transportation? Does one or more persons in your family stay at home during the day? Do you have very young children? Where do they eat? Where do they play? Where do they nap?
How do you manage your household? How often you eat at home? How often do you cook at home? How many people use the kitchen at the same time? How many dishes do you have? How many pots and pans? How many small appliances? Do you keep any appliances on the kitchen counters? How often do you shop for groceries? Where do you store them? How big a refrigerator do you need? Do you have a separate freezer? How far do you have to walk from the garage to the kitchen? Where do you put your garbage? Where do you do your laundry? Where do you store your laundry supplies? Where do you store your cleaning supplies? Do you have more than one vacuum? Where do you put your mail? Bills? Magazines? Newspapers? Packages? Do you use a shared family calendar? Do you have pets? Where do you keep their supplies? Their food?
What do people in your family do when they come home? Do you need a space for children to do homework? Where do you watch television? How many people watch television at the same time? How many televisions do you have? Do you have a shared family computer? Do you have a work at home computer? Do you need a separate desk for working at home? Do you need a reading chair? How many people eat dinner at the same time? Would you rather eat in a separate dining room or near the kitchen? When do people in your family go to bed? Do you need to have quiet areas for sleeping while other people are still awake? Do you take a shower or a bath before bed? Where do you put the clothes you wore today? Do you need a space to lay out your clothes for the next day before going to bed? Do you read in bed? Watch television in bed?
What do you do on the weekends? Do you have hobbies that need storage space? A workshop? A crafts room? A library for your books? An office for your computers? Do you need to store bicycles or kayaks? Exercise equipment? Christmas decorations? Where do you store your suitcases? Where do you store your seasonal clothes? Do friends and family come to your house? Where do you gather? Do you need a large dining room? Do you need a room for overnight guests? Do you need a separate area for children and their friends? Do you use your backyard? Do you cook outside? How far is it from the kitchen? Do you need an outside play area?
This may seem like a daunting list of questions, but if you are going to spend the money and energy to build a house, then you should have all the spaces in that house that will allow your family to be comfortable and efficient. Once you decide how you live, it's a lovely fantasy to give everyone their own bedroom, their own bathroom, their own workroom, their own entertainment area. But even if you could afford a 10,000 square foot house, do you want to clean it and take care of it? That's why you need to think about multifunctional spaces and not Rooms. Maybe it's time to do away with that living room that you only use to set up the Christmas tree once a year. Maybe it's time to do away with the formal dining room, when you always eat in the kitchen. Maybe it's time to do away with the double oven and large kitchen sink, when you never cook. Maybe you need a larger refrigerator for left over take out instead. Maybe a desk or small area near the garage door or the front door to store cellphones, purses, and briefcases would be more efficient than another bedroom that you only use for junk storage. Maybe a separate playroom would be better than a scattering of toys in the unused living room. Maybe a dedicated study would be better than scattering papers on the kitchen table. Maybe you don't need a dedicated craft room, if you have a craft cabinet in the kitchen or family room. Only you can tell what spaces are necessary for your lifestyle.
Once you know what spaces you need, now you have a plan that you can bring to an architect. And you have a plan that you can use to evaluate the design that the architect draws up.