If the Sun is exalted in the 10th house, should the South also be improved, or should Sun items go only in the East?
Sun items go in the East, but they can also go in the directions of the friends of the Sun; one colour or one showpiece is not restricted to one place. That is why the colour combinations of friend planets were given.
Related questions
Where should a construction company's office be?
Construction belongs to Mangal, so the office should be in the South zone, with its door in the East.
Why is sleeping recommended in the South-West or the South?
Sleep is an activity of Saturn, and Saturn is a friend of Rahu-Ketu, who rule the South-West. The South is the seat of Yama, before whom no one prevails. Sun and Saturn are enemies, so sleeping in the East brings husband-wife quarrels; only a king-like person such as a politician or minister can sleep there. Applying this friend-enemy logic of the planets to every activity lets you derive remedies yourself.
As an interior designer, clients choose their own colours and I cannot check their planets; should I give a remedy or try to convince them?
Do not try to convince anyone. People mostly like the colours that match their own planets. If a client chooses an anti-element colour and their kundli allows it, never stop them; it will bring them benefit.
Can a mirror be fitted on a wardrobe in the S, SSW, SW, WSW or West?
No. Wardrobe mirrors also belong on the North or East wall. Some say the North-West is also allowed because the mirror represents the water element and the Moon.
Can a nandavart dwar be made in a flat?
Yes, it can be made in a flat too.
Can a person whose Sun is debilitated (neech) have the drawing room in the East?
Yes, with remedies; he will not leave the East unused or build a toilet there. A drawing room is not a permanent seat. Only permanent seating, such as an 8-hour business seat, should not be chosen in the zone of a debilitated planet.