I have the following:
1) 1 SDD that I work on and another that is mirrored every day. If one disk fails, I have another. This is my working disk.
2) Incremential backup of data that changes often, like emails or some directories I work in. Mostly use if I delete a file by accident. Just copy it back and be done. This goes to a NAS.
3) Data that does not changes often, like movies, images and music is stored on a NAS.
4) Second NAS to backup the data of the first NAS.
5) Essential data (less than 10MB) is put on my website on a personal directory. This is data that I might need in case of the house burning down.
So when something goes wrong (unless the house burns down, but the I have other problems and my music is not one of them.) I have a way to restore it.
The most important thing however is not to backup, but the knowledge on how to restore it. You need to test that out from time to time. I have people seen who did backups to /dev/null to test it and forgot to remove that parameter.
What you can do if you REALLY need to have things off site, like photos and other things that you can't replace is just buy a dedicated HD that you put this data on and keep it in a drawer at your office. Once a month or so you take it home and add the new data.
And if that disk is full, buy a new one or a bigger one. If data is really THAT important, the price of the HD is well worth it.
But again, test the restore.