Windows 10 Updating existing system image backup

Depends on what you are using but most systems (like the free version of Macrium Reflect) gives you many options which include making of a complete new image each time of making an initial image folllowed by "incremental" update. To keep things simple in the event of needing to recover a full or part system I prefer to make complete backups keeping three "generations" deleteing the oldest of the three each time I create a new one. The size of the backups will vary depending on how you use your storage space. My system drive contains only operating system, installed applications and system files/folders. All user data is stored on a separate physical or logical partition. In this way my compressed backup images (of a Windows 10 sytem and masses of apps) are never more than about 20GB in size.