Indecisive buyers are a common cause of property sales falling through before completion, a survey claims.
Two-fifths of the owners asked said that buyers had changed their minds or found another home to buy, the survey for the Homeowners' Alliance found.
This was a more common reason for deals breaking down than a mortgage failing to be secured or a problem further up the chain, it suggested.
Recent data showed UK owners are moving less frequently than a decade ago.
The research, undertaken by Savills for BBC News, showed that before 2008, homeowners moved, on average, 3.6 times after buying their first property.
In recent years, the slower pace of buying and selling suggests they will move, on average, 1.8 times over their lifetimes
The Homeowners' Alliance survey suggested that sellers typically had five different potential buyers view their property when it was on the market.
These sellers could lose thousands of pounds as a result of deals falling through at the last minute.
Paula Higgins, chief executive of Alliance, said: "We often hear about would-be buyers losing their dream homes as a result of sellers accepting higher offers but less is said about sellers forking out thousands in wasted fees only for buyers to change their mind, leaving the seller back at square one."
Samantha Kempe, co-founder of property buying business IMMO, which also conducted the research, said: "Sellers should be able to proceed with the sale of their property knowing what price they will receive and feeling assured that the sale will go through."
The latest figures from mortgage provider the Halifax suggested that weak demand for properties meant UK house prices saw the biggest monthly fall for nearly eight years during April. The lender said prices fell by 3.1% between March and April, the biggest decline since September 2010.