Path of Exile Trade Etiquette 101

If you have items listed for trade ===> Respond to requests!
Not doing so is wasting time of buyers.

If you just started a boss fight or are busy and know you won't be able to respond, do a quick /DND as soon as you can.

If you forget to /DND and are in the middle of a battle, It takes 2 to 3 seconds to press enter, type "1 sec" and press return at a moment where you can. This is well received by buyers as you took a moment to let them know instead of rudely ignoring them.