The trick to a whole-house palette is restraint and a shared backbone. You don't want every room to match — you want them to *belong together*. Here's how the good decorators do it.
Start with the constants. Pick one white for ceilings and one colour for trim (skirting, architrave, doors) and run them through the entire house. This is the single biggest thing that makes a home feel cohesive — your eye reads the consistent woodwork as continuity even as wall colours change. Farrow & Ball Wevet or Pointing make lovely whole-house whites, or Little Greene's slightly warmer shades work a treat in older properties.
Then build a family of 3-5 wall colours that share an undertone. Don't mix warm and cool — pick a lane. A warm scheme might run from Skimming Stone through Cornforth White into something deeper like Mole's Breath for a snug or hallway. They're all from the same tonal family, so transitions feel natural rather than jarring.
Let light and use decide placement. North-facing rooms drink light and pull colours cooler and greyer — give those rooms your warmer, higher-LRV shades. South-facing rooms can take deeper, moodier colours like Hague Blue or Studio Green without feeling like a cave. Hallways and landings are the connective tissue — keep them light and let them be the neutral thread that ties the bolder rooms together.
The "but what about open-plan?" question: where rooms flow into each other with no door between them, either use the same colour throughout or change only on a clear architectural break (a chimney breast, a beam, a step).
Practical bit: buy sample pots of your shortlist, paint big A3 patches on lining paper, and move them between rooms over a couple of days. The same colour will behave completely differently in your north-facing kitchen versus your south-facing lounge. Trust what you see at 4pm, not what you saw in the shop.