Pietro Montalcino is right. Dropbox has been my Home folder for several years. I store nothing of value on the computer’s drive, other than system files, applications and library data. Everything else is in Dropbox. And by doubling the storage capacity (mine has now jumped to 206GB instead of the 106GB I have been paying for hitherto) Dropbox has made it a no-brainer to treat Dropbox as your main data location.
Replacing your home folder with Dropbox has two advantages. First, it makes available all your data on any Mac and, in with certain provisos, on any iOS device. Second, it ensures that everything you do is backed up to the cloud as soon as you’ve done it. Even if you have no other backup, Dropbox is reliable and will likely as not get you out of trouble if the worst happens.