When I'm in buying mode, I check every hour or two. When I'm selling, it has happened that I've had offers within fifteen minutes of posting. Other times, no offers for a month, even though hundreds of hits have been registered on the ad. I think that there are a lot of Audiogoners so the odds are that somebody is watching, especially pros who may be looking to flip a purchase for a quick profit if something appears underpriced. Also keep in mind time zone differences. You check at midnight in the eastern time zone, then go to bed. It's prime time in the west and if they're looking for the same thing as you, it's too late when you get up the next morning.