I use Acronis True Image(but Macrium and Backupper also work well) and I keep a 2TB USB drive that holds nothing but backup images of the system drive. I also usually only keep the most recent 3 or 4, HOWEVER; I also rotate 3 separate but similar SSD drives(500GB) in 2.5-3.5 adapter cases and have my C: drive and 2 recording drives in a 3-slot drive tray for easy swaps. The 3 system drives are:
#1-Newest version of Pro Tools(2019.10 Ultimate today)
#2-Previous major version(12.4 HD)
#3-Last new version of 2019(.6 IIRC)
If I download some new software or update, I will clone over #3 FROM #1>Install #3 and install the new software and/or update to that(making #1 the most recent "GOOD" setup). Doing this allows me to try anything, knowing I have a backup plan if something goes south(Imaging works fine, but I may not have time for that and need to get work done).
Samples drives get imaged BEFORE I install anything new.
Recording drives; I am more likely to save session copies to multiple external drives and to both my recording drives(files change too often for imaging to be of value). I have 12TB of NAS and another 8-10TB of external USB3 drives). Staples currently has 6 and 8 TB USB3 drives on sale($119 and $149)
