Until Windows 10 came out, there were the options to decide if, how and when updates were installed. In those halcyon days, Windows had a feature update life of five years and a security update life of 10 years.
With Windows 10, Microsoft have not just moved the goal posts, they have completely demolished them and replaced them with very cheap replicas. Now Windows 10 versions have a feature and security update life of up to around 18 months. Effectively, Microsoft release a new version of Windows - the latest is 1803 - every six months or so. They are all called Windows 10, which I guess is the maximum number of months they expect any particular version to be used for.
To get around the appalling reduction in support life, each new version is free to existing Windows 10 users, and they try and force all Windows 10 systems to go through the pain and confusion of a version update every six months or so.
The Windows 10 versions so far have been 1507, 1511, 1607, 1703, 1709 and 1803. The next one due out in the fall is expected to be 1809.
Whereas the monthly major update cycle can normally complete an update in well under 30 minutes, the version upgrades can take much longer. My worst experience so far was an upgrade from 1709 to 1803, which failed six times at around an hour a time plus a 3 GB download (good job my ISP is uncapped). After that, it took a further four attempts with manual intervention, each one being more destructive than the previous one, before 1803 was installed.
That final attempt involved completely reinstalling the original Windows 10 system (1607) that came on the PC and which I had fortunately backed up as a disk image; then applying the 1803 upgrade, reinstalling all my Apps, getting rid of all the Microsoft bloatware, then a couple of hours going through all the settings putting them back the way I wanted them. Total computer down time was over 24 hours and it would have cost me over 20 GB on a metered network.
I prefer my computers to work consistently for several years without any major changes or trauma. I don't like having to do a major sort out every six months.