I have had my 1TB TM from Aug 2008 and still have 302.47 GB remaining for backups. A strange situation has happened for the last month+ where 302.47 GB of space has remained the same. It continues to do hourly backups, and the new files appear to be there. However the 'available space' remains just set at 302.47. I do see on occasion, expired backup thinning happening. However, today I have had 2, 20GB backups happen and no affect on available space. My expectation is that the available space would be reducing even with the expired backups being delete. Or, the earliest back would be changing from the original date I turned on TM on Aug 11/08. I have used the Monitor utility and it shows the same 'space free' GB value. I am a PC convert (since mid 2008) and was wondering if I should be concerned? "Once you go with a MAC, you will never go back!"