I have just spotted Time Capsule 500GB's and 1TB's on the Apple refurb store and wondered if it's big enough or even if I need it? Basically, I will be using it with a Mac Mini to start with but then when the iMacs are cheaper, I'll be using it with that too. When I get my Mac Mini next week, I will be upgrading the hard drive to 320GB(or maybe 500GB) then I will be getting an enclosure for the 2 x 500GB hard drives out of my old PC. How exactly does the time capsule work? If I have say 500GB of data in total, will it make several copies of the full 500GB or does it just back up the files that have changed? So, again, if I have got 500GB of data, would I be ok with a 500GB TC or would I need something bigger? (my one drive from my PC currently is full but it has several copies of stuff and really needs sorting so it may get reduced to half, but who knows lol). Would I be better using a USB drive for Time Machine instead?