I think it's a good idea to put up an ending time, buyout, minimum increments, etc... If you don't have any of those things, it just seems like you'll keep the auction going until you get a good offer, which is against the rules I believe.
I'm interested, but I won't bid until I know an ending time.
I apologise but I am an adult and I have a working life. I will PM the current highest bidder (who hasn't retracted their bids) and see if they still want the item. Otherwise I will reopen the auction that will end at 11pm tonight (UK time).
I don't want to add a buy out price and I don't want to add a minimum increments bid either, bid appropriately.