I will mention as well to look down the road at what parts of your build will be the most important to you in 10-15yrs. Dont know your kid/family situation. I saw her Dad go down hill fast and knew this was our forever home so I did everything handicap accessible. All 3-0 doors, even put blocking in my walls before sheetrock for handicap bars in bathrooms and my shower. Hope I never need it. Oh and blocking everywhere you might hand a TV, thats been helpful.
Also I sunk extra $ into a few things Im glad I did. Bigger garage and mud room, master bath and closet. After 10 years Im realizing in 6-7 more our kids will be out or on the way out completely and we will have a HUGE empty nest. Needed the space at the time.
I put extra$$$ into my back porch because its my outdoor kitchen. We spend a lot of time there watching ballgames, cooking, and entertaining guests. Also a large front porch and sidewalks. I got concrete on 3 sides of mine and river rock on the 3rd. Mine has almost zero wasted space. I see floor plans where Im not sure what people are thinking. Things like fancy ceilings and wasted space are not necessary and add cost. We thought out every detail months-years before we ever started. Even put the Wife's pantry and utility room facing her side of the garage so I could build a doggy door to slide the groceries straight in from the garage. If anything happened to mine I would build it back the same, but this time a GC will do it. It wore me out.

Its not the will to win but the will to prepare to win!