I used to have three cleanup apps on my Android phone. Clean Master (an old habit and since pulled from the Play Store), AVG Cleaner, which a friend recommended, and CCleaner, which I grabbed once ...
Task Manager has always been my first reflex when something feels off. If my PC slows down, I press Ctrl + Shift + Esc, glance at the Memory column, and see that the RAM usage sits at 80 or 90 percent ...