I have also seen agents list the house as having one fewer bedroom or bathroom. While those who go to see it are pleased to get more than they thought, the reality is that the home was taken off the lists of several buyers who needed (or at least thought they needed) that extra bedroom or bathroom.
Lot size is pretty easy to get, you just have to check tax records, yet.... I see tons of listings everyday that the lot size is incorrect, or not listed at all, and also incorrectly indexed.
Square footage is difficult. I encourage my buyers not to search by square footage. Many agents don't list the square footage at all and the agents who list it often get it from tax records, which are often incorrect or hard to read. But, realize that many buyers do search by it and if you don't have the square footage indicated, or it is listed as less because the tax records are wrong, you are getting fewer buyers.
And, perhaps the worst mistake of all.... incorrect school district, or failing to list a school district altogether. I see this error as much as I see any other. And, I assure you that this one thing can affect your listing as much, if not more, than any other. Especially if your home is in the suburbs in a community that appeals to families. Make no mistake that the biggest single criteria I get from families with children is school district. Sometimes it is just one district that they consider, sometimes it is a list of three possible school districts. And, it isn't always just based on academics. Sometimes it is an awesome athletic department, or an awesome theatre department, and awesome technology department, or an awesome media/journalism program. So, if your agent doesn't want to spend the 10 minutes or less necessary to determine your school district, then you could be leaving thousands of dollars on the table.
And, today's real estate search engines - whether it be MLS used by agents, or consumer sites such as Zillow and Trulia - can break it down even further. We can narrow a search down the most minor details. If your home has granite counterops, but doesn't get listed as having granite countertop, then the buyer who won't buy anything without it....never sees your home. And, this is just one feature. You can search for whirlpool tub, garden tub, hardwood floors, trey ceilings, separate living and dining rooms, formal dining room, lot size, square footage...you get the picture, and that is a very, very small list.
The point is to list the home accurately so that the buyers that your home fits the best actually come and look at it, and to have as many of those buyers as possible. That is how you get the best possible price for your home.
So, once you have your home listed. (even if it is listed with me) Ask for a copy of the listing and then go over it. Check how they describe the home, but more importantly, make sure all the 'facts' about the house are correct. Otherwise the buyer who were hoping for is not even going to see your home, other than when they are driving by to look at another home for sale in your neighborhood.