One of the biggest mistakes I see people make when they list their home for sale has to do with the expiry date of the listing. The Toronto MLS system has a minimum listing period of 60 days but has no maximum. Too many sellers don't pay enough attention to this important term.
There is NEVER a reason to list your home for an extended period of time no matter what you may be told. Why would you lock in for a long period when you can simply extend or renew the listing if all is going well? My suggestion is to list for 90 days maximum.