Questions & Answers about Un buen descanso es importante para la salud.
Both are grammatically possible, but “un buen descanso” is the most natural and common in this context.
In Spanish, many adjectives commonly come before the noun when they express a general, subjective quality (good, bad, big, small, etc.). Buen is one of these.
- Un buen descanso – sounds natural, like “a good (proper) rest.”
- Un descanso bueno – correct, but sounds more like you’re contrasting it with another rest that was bad, or you’re adding the adjective as new information: “the rest was good.”
So for a general statement like “A good rest is important…”, “un buen descanso” is the usual choice.