Most rooms are not missing a sofa. They are missing a decision about what deserves to stay.
When we are called to a Bundaberg house, we start by taking things away. A side table that was only ever a landing pad. A cluster of frames that no longer belong to anyone in the house. A rug that is almost the right colour and, for that reason, is worse than a bare floor.
What remains should be able to stand in the light from the veranda and still feel finished. If a gap is left, we fill it only after we are sure the gap is real. A single branch in a wide vase will often do more than a shopping list.
Try this at home, in one room, on a Saturday morning: take out everything that is not furniture or a lamp. Put back only what you would keep if you were moving house tomorrow. Live with the quieter version for a week before you buy anything at all.