The time range is set for an auction from 1 day to 7 days. From my personal experience in auctioning, the time for auction should be short and an auction should take place at a swift pace. The opportunity to get a Knight should be for those who are fast, pay attention to the auction and keep track closely of other bidders.
I would recommend that the time range should be between 12 hours - 7 days at maximum. This recommendation can benefit sellers when they can sell their Knight quickly and also benefit bidders who desperately need the Knight they want.