Worn-out and Worn-down

Worn-out adjective - Depleted in strength, energy, or freshness.

Worn-down and worn-out are semantically related in health topic. In some cases you can use "Worn-down" instead an adjective phrase "Worn-out".

Worn-out and worn-down are semantically related in exhausted topic. You can use "Worn-out" instead an adjective phrase "Worn-down", if it concerns topics such as used.