Drying vs Curing

A cake is set on top long before it's cooked through. Paint is the same. A tin of emulsion might say it can be recoated in 2 to 4 hours, and that tells you nothing about when the film is hard enough to take real wear.

Touch dry means the surface no longer feels wet or sticky. Recoatable means the next coat can go on without disturbing this one. Cured means the film has reached its full hardness and toughness, which takes days or weeks, depending on the paint and the room. Each answers a different question, so read the tin for each one you need.