Length of Auctions

Can anybody tell me what decides the length of time of an auction?

As far as I can see it is fairly random, whenever I put a player on the market the time seems different. Even when I tansfer list two or three players together, their times vary greatly.

Is it down to quality or price or the time of day or general state of the market for that position?

Curious about the same thing

I'd love to know this as well. I've noticed that if you list a player late at night that the auction usually lasts for about 5 hours but I think its pretty random.

I used to think it was down to age but not sure!