“More free memory is always better”
macOS uses memory for useful cache. Sustained pressure matters more than an empty-memory target.
“Every cache should be deleted regularly”
Active apps recreate caches, sometimes with large downloads or long rebuilds.
“Every background item slows the Mac”
Many provide essential sync, security, device, update, or backup functions.
“A large file is unnecessary”
Size does not determine purpose. Personal media, backups, projects, and virtual machines are often legitimately large.
Use optimization to address a specific measured symptom, change one variable, and verify the outcome.