Bubs wrote:Thanks both.
Newest one is 10.6.8, old one is much older ....
10.6.8 has Time Machine, all you have to do is plug-in and format a USB/Firewire disk. However, this is not foolproof, as it really only keeps a track of your current stuff - if you deleted something, and then two years later wanted to restore it, you might be out of luck.
If you are using iPhoto for your images you are able to export whole catalogues of images - I suggest DVD is a good medium for doing this. Just export a month/event at a time - or more if you can get it on a single DVD.
As to the upgrades - more recent ones are all free. I think you may have to pay for 10.7 - yes £14.99:
http://www.apple.com/uk/shop/product/D6 ... /os-x-lion
10.8 is the same price:
http://www.apple.com/uk/shop/product/D6 ... ntain-lion
10.9 and after are free upgrades.
With any upgrade you will need to check whether your machines will support that OS. With 10.6.8 you can go straight to 10.9+ (latest is 10.11) if your machine supports it.