Each rating list runs for five years, and may change within that time. The value from the very start of the list can be altered, or events within the life of the list (such as an extension) can be reflected by changes within the list, leading to different values at different times. For example, a property is entered in a rating list at 1 April 2005 with a rateable value of £10,000, and a year later the property is extended causing an increase to £12,000 from 1 April 2006; the original entry of £10,000 remains unchanged for the first year. A successful proposal could alter this original value of £10,000 to £9,000 from 1 April 2005 to 31 March 2006, but the second entry from 1 April 2006 would remain unchanged at £12,000.