The primary suite is one of the easiest places to waste enormous amounts of square footage.
Start with what the bedroom actually needs: bed, nightstands, circulation, perhaps dresser, chairs, television.
Once those fit comfortably, adding another few hundred square feet may simply create empty floor that needs furniture.
Ask how you really use the bedroom. Some people only sleep there. Others read, work, watch television, drink coffee, or spend significant time there.
The view may matter more than size. If you paid for waterfront or another extraordinary setting, consider what you see from the bed when you wake up.
Privacy is critical. Large glass walls are beautiful until neighboring houses can see straight inside at night.
The bathroom and closets may deserve more attention than bedroom size.
Think about shower, tub, dual sinks, toilet compartment, storage, natural light, and actual daily routines.
His-and-hers everything may be appropriate in some luxury markets, but do not build it simply because expensive houses are supposed to have it.
Closets should be based on real possessions and movement: wake up, shower, get dressed.
Keep laundry proximity in mind.
If the suite is upstairs, a small coffee or beverage area may be surprisingly useful.
Think about aging too: curbless shower, wider doors, and accessible circulation can be almost invisible today but very valuable later.
Build a retreat, not a monument.