My personal opinion is that online backups aren't meant for large files. They take forever to upload and 10 times longer should you ever need to restore from the backup. I mean uploading 500GB of file will take a week or two, then if you had to download those files, you're looking at a month minimum to get them back. Then there's the entire issue of cost, because actual working files will be much larger in size (mb) than the average jpg of the grandkids mom and pop are backing up so more GB = more $$$.
I use a range of external hard drives with and without RAIDs configured. I don't like NAS because even that is limited in speed by the network speed. A direct hardwired connection via Firewire/Thunderbolt/USB3 is much faster than most networks in my experience - so faster than any NAS setup.
And since the external drives are connected to my main workstation, which is always online, I can can connect to that system from anywhere over the internet or even just over my local WiFi network and grab a file if needed.
Automated backups run nightly, weekly, and monthly. Once a quarter I back up to an external drive and put it in a safe deposit box at the bank.
Also, Adobe applications have an auto-save feature - At least Photoshop and Illustrator do. They have for some time. You can set this to a time interval which you feel works for you. In some cases it can be very handy. I tend to set mine for a couple hours between auto-saves because I'm already in the habit of hitting command-s often after years of working without any auto-save feature. So, I don't need it every 10 minutes and chances are great for me that if I'm making a quick change to something that 10-minute auto-save may overwrite something I don't want it to overwrite. But, your milage will probably vary.
And other than the one-time cost of the drives, this is a free solution.