I totally disagree on this although I might have agreed with Windows XP and earlier. There are utilities built into Windows 7 (and later) that make reliably disc cleanup painless. In addition the Windows install option of keeping your old apps, settings, etc. have come a long way. Having done about a dozen or so upgrades I can speak from experience that the process works exceedingly well. Many of the updates/upgrades I have done have involved just going to an SSD and moving Win 7 to Win 10 on both HDD's and SSD's.
I can remember many years ago people recommending that every couple of years you should format a drive and reinstall Windows. Why I will never understand except it was written by people that wrote web content and magazine articles. Having said that it was lucrative in my sideline business. But back 15 years ago people purchased things like Office and got the product on a CD. These days, all too often the product is delivered electronically with a product key that gets lost, often requiring a repurchase.
I agree that Windows has come a long way and it is nothing like it was in the W7 days, but just from my last install the Windows directory shrunk from 7.54g to 6.85g with the bulk of the savings from system32 and syswow64 but others as well. Boot time was reduces as well. It's probably not as necessary as it was with W7, but it does start clean and gets rid of things that accumulate over time.





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