New to iMac and just getting to grips with the whole kit (having been a DOS and MS Windows person since time began). Have set a 1TB external HD to act as Time Machine. I see that when Time Machine gets towards its full capacity it cleverly deletes old files. Despite reading though many of the FAQs etc I can't seem to find an answer to what I hope is not too stupid a question. Are any unique files deleted? What I mean is - will at least one copy of every file always be there - regardless of the length of time since it was last accessed or modified? So - in X number of years, when the drive fills and starts to auto delete will I still have available what was on the very first backup? Maybe it is a stupid question - I'm sure if really old stuff was likely to drop off there'd be some sort of warning!