Three sources, and warmer than you think

The working minimum is three sources at different heights: something overhead for cleaning and finding things, something at seated eye level for reading, and something low and warm for the evening. Once there are three, the overhead one can mostly stay off, which is the point.

Colour temperature does more work than brightness. Warm light around 2700K reads as domestic and relaxed; neutral light nearer 4000K reads as functional and, in a living room, faintly clinical. Colour temperature is printed on every bulb box and is the specification most people never look at, which is why so many newly rewired rooms feel like offices.

Mixing temperatures in one room is the mistake that follows. Replace bulbs in matched sets rather than one at a time, because a single cooler bulb among warm ones is visible immediately even to people who could not tell you why.

Dimmers are worth the cost on the overhead fitting and nowhere else. A dimmable ceiling light turns the least useful source into an adjustable one; dimmable table lamps solve a problem that turning them off already solves.

Aim light at surfaces rather than into the room. A lamp throwing light onto a wall or a bookshelf produces reflected, even illumination; the same lamp pointing outward produces glare and a dark ceiling.