No less than 7 days - and you don't pay any more or less for the 7-day auctions, so I'd stick with those. Also, from my experience, auctions ending Sunday and Tuesday seem to do well. (The reason 7 days is good is so even if a person only checks eBay once a week for new stuff, they'll be sure to find yours.)

Mlle, I was gonna say the ending day is important too. I try to end mine on Sundays. That way you have all weekend for people to find you.

The only time I do a 3-5 day auction is for higher priced things to begin with, ie my husbands guitar. We sold it for $3000. I'm not sure exactly why it sold better as a short auction instead of a 7 day, but it did. We did do another guitar for the 7 day and it sold about $1000 less. I also have listed some pregnancy cd's for the shorter time frame and they did well too.

And I agree totally with the above posters about the end time. Since we are on the West Coast, we always try to have our auctions end about 8pm on Sundays for the East Coast people. Works out great!

Good luck!

Just wanted to add that turbo lister can be downloaded for free, and you can list when you have time and upload at your convenience.  I don't stress over times--I figure that if I have time to list it, someone else like me has time to look at it.  (Just think of all the mk consultants trying to do anything to avoid calls or WARM CHATTER!!!!)