With these great updates coming out like wildfire, I haven't as I figure you can roll back on Splat.  I make an Acronis image file every other month or so of the C drive, but all other stuff (on other drives - audio, sessions, etc) are duplicated on externals.
 
Sound safe enuff??
 
Speaking of Acronis, I bought some 64 gig USB drives, so I could store them off site.  Those should work ok, eh?  My .tib Acronis files should fit on that.

I also use Acronis. I also back up before installing an update. However, I back up the schmeer, the entirety of my internal hard disk set at the time of the back up. Generally I backup weekly - to an external drive. You never know.

I haven't either.  My project data is backed up every night. 

I backup/store most of my important stuff on an external 2TB drive. I then mirror this to another set of 2TB externals and keep one offsite. I swap them around every month or so. I also tend to create DVD archives occasionally of very important files.
 
I use Macrium Reflect Free for imaging purposes.

Non stop acronis backup shop here. Backup to my NAS that has RAID5 which in turn is backed up to an external drive. All my PC hard drives are mirrored. People who don't backup are either crazy, or in denial, or will eventually end up learning the hard way.

I back up projects periodically.
 
I have an external drive. I do a substantial backup before formatting the drives and installing Windows 10.
 
Normally, I don't backing-up anything before for Sonar updates.
 
I do like Gobbler.
 
 

yeah...thx guys.  I'm especially interested in hearing the frequency of users backing up before a Cakewalk update.  Not that it takes weeks to do one...but I haven't yet.  :-O
 
 

Up to you. I do a full backup every week, data every night. If I'm updating software I do it straight after a full backup.

Pretty much an identical technique to yours for the last 15 years mixmakr. Project/audio/data files backed up to duplicate drives nightly using viceversa pro. These backup drives duplicated to a second copy weekly again using viceversa pro. C drive monthly using Acronis. Haven't been caught out yet:)

I run a Windows Home server which after doing an original image of all connected computers on the network, does incremental backups every night. I do a manual image just before installing any new Sonar updates.