I can't imagine how Windows can be used without maintenance.
CCleaner is completely safe and irreplaceable, but that alone is not enough. Really need something more and very well complement each other CCleaner + Wise Care 365 + Advanced System Care
Things like GlaryUtilities, Revo Uninstaller, WinUtlities, Privazer, etc. would really be wise to avoid.
Recommendations should not be shared if you have never used the thing yourself or do not understand exactly what it does and how it works.
The operation, usefulness or harmfulness of any thing does not depend on what one thinks, but what this app really does or what it not do.
But in the end of everything, everyone has to decide for themselves what they use and what they don't use. The most important part of this is always the part between the back of the chair and the keyboard. And that's really the most important thing.
CCleaner is completely safe and absolutely necessary, but it alone is not enough, something more is also needed. So decide yourself and don't listen what somebody thinks. Think yourself.