I have a system that works well for me.
I have a 2TB external expansion drive that I back up to every day, keeping 10 copies, the oldest replaced by newest. This runs through a USB3 cable so is pretty fast.
I also have an extra 2TB internal hard drive that I back up to every Sunday. I keep 7 copies, the oldest replaced by newest. This is very fast.
I actually tried many of the backup software packages out there and many seemed to be less than stellar (IMHO). I found a free software call DataSafe (
http://www.sofgem.com/products/datasafe.html). It is old but it works very well. It is automatic (scheduled) so I don't have to give it much thought. I do check my log every morning to be sure that the backup size seems consistent with what it should be. Occasionally I flip through the backup to be sure it looks intact. I have seen no issues to date.
I do not compress my backups as I find if I need to grab a file from the day before I don't have any hoops to jump through. Just a matter of grabbing the file from the right folder on the right hard drive.
I used to back up only occasionally, but decided last year that this was not very smart since I have tons of client files with new ones created daily. In all my years I have never lost any data to a malfunctioning hard drive, but it is better to be safe than sorry. I have occasionally lost a file to a program crash, so it is nice to be able to go to my day before backups and grab the previous version.
There are some backup programs that will backup as you work, but I have never found a need for that and the one I tried seemed to use many resources that inhibited work in progress in the many resource intense programs I have running constantly, which might include a couple CAD programs, Photoshop, Illustrator, MS Word and other reference materials.
Hope this helps.