Yes, a FULL install is very time consuming and a PitA to do.Just an update replaces all the system files. That might well be enough.
I keep all the "garbage" as you call it, so I don't have to spend days reinstalling everything.
My systems all date from Windows 7, then 8, 8.1, 10 and all its versions, and they are fast and reliable. I see no need to do clean installs. Even when I get a new machine I don't do a clean install (I clone from another machine).
But I am disciplined and clean and tidy. The garbage gets taken out.
And it is worse on Win 10. The post install update can take a LONG LONG time to run.
I started Windows from Win 3.1.
Some updates went fine, others had issues.
I get leftover garbage from:
- Repeated updates of various software, which don't always update nicely.
- Program delete/uninstall, that do not completly uninstall, and leaves stuff behind: directories, files, registry entries and other stuff.
- What ticks me off here are software that installs say 5 programs, but the uninstall only uninstalls 4, leaving one behind still running, taking resources and sometimes conflicting with other software.