I'm sure you don't create an image before every program update.
As it takes many hours to complete, especially if you have more than 50-75GB on your hard drive.
Not necessarily true.
Depends on system hardware: SSD 120 GB (SATA III) to 500 WD Desktop (SATA III), both running as SATA II, a full disk image will take only 12-14 minutes to complete. Amount of data in image: 15.7 GB, normal compression. With the old WD 80 GB SATA II operating system drive, took a little longer: 15-17 minutes.
WD 80 GB drive compressed to 23-27 GB with about 37-40 GB data. SSD 120 GB drive compressed to 15.7 GB with about 27 GB data.
Incremental backups of operating system drive will take as little as 2-3 minutes.
Even Windows 98SE using Norton Ghost full disk imaging on late 90's system with maxed 128 MB RAM never took that long, 12 minutes tops.
But then, we're talking only 2-3 GB data, including Windows.