A working notebook
Less space.
Better decisions.
Short notes on planning a room, keeping useful measurements, and making things fit.
Start with the door
A floor plan is more useful when it includes movement. Mark the swing of every door, the path to the window, and the space a chair needs when someone is sitting in it.
Keep a measurement card
Write down wall lengths, ceiling height, and the distance between sockets. Keep the date with each sketch. A simple record is easier to trust than a photograph taken from an awkward angle.
Leave one quiet surface
A shelf does not need to be full to be useful. Choose a place for things that are in use today, and a separate place for things that are merely waiting.