What I would recommend both sellers and potential buyers do is to 'subscribe to topic' on the thread so that notifications are received when someone posts something (and is cleared). To subscribe, just click on the tab on the left side of the screen immediately above the thread content.
So often we see posts on a seller's thread where s/he has not responded and knowing we can all be busy at times and not able to check-in frequrently, at least the notification shows something has been written to then check