I see where a single item per listing makes sense. Easier to click and look at an ad for one thing, can close it when that one item sells as you mentioned, etc.

I guess making individual listings isn?t any more time consuming for me than making one big, long listing with everything in it.

Also, a bulk listing would just have a generic description in the title and someone would have to click it and scroll through everything to see what I was selling. A single listing would have that particular item description in the title so people could see the title and decide if it?s something they are interested in without having to open it.