Consider your lighting preferences during the initial design phase of a new build or renovation. For example if you want three pendant lights over your dining table instead of one or two that should be taken into account before construction starts.
In a renovation on the other hand we have to consider what effect a new skylight will have on the efficiency of the existing building. In some cases the additional sunlight (and therefore heat) can help reduce the amount of energy needed to heat the house. It depends greatly on the local climate but also on the design of the building envelope of the house.
Wall washers either installed on the wall or aimed down from the ceiling are used mostly to highlight decorative features such as an art piece or a textured finish like a brick wall. However the psychological effect created by lighting the walls can make the whole room feel much brighter.