Roll Back File Version using DropBox
Drop Box keeps previous file versions for thirty days, so if you sync your current project folder to Drop Box, and you have a decent connection, then if you were unlucky enough to suffer from a corrupt PSD or TIFF file with lots of layers and hours of work involved, you could roll back to the last OK version. Note this is just a thought, and I have not tried it.
Recover older versions of files - Dropbox Help - Dropbox
Something else I have just discovered, you can increase your Drop Box allowance from the initial 1Gb to a more useful 10Gb of free storage, by installing the Drop Box app on multiple systems, with each new installation giving you an extra Gb. You can then access the full amount from any of your systems, and you don't loose the additional storage even if you never use the other systems again. Just a thought, but one I shall be looking into.

