Overpricing to leave room for negotiation is the specific version of this mistake that costs the most, since buyers and their agents can see days on the market accumulate and start to wonder what is wrong with the house rather than simply offering less.
Skipping a pre-listing home inspection, typically $400 to $600, is the second common mistake, since it means a buyer's inspector gets to raise the first issue during negotiation rather than the seller addressing it, or pricing for it, ahead of time.
Both mistakes come from the same root cause: relying on assumption instead of current, specific evidence about this house and this market. Get your hand-reviewed valuation from Joel Dyck.