RAM + almost full

Reboot frequently or shut down at night. That will clean out temporary system and app cache and swap files.

Once every couple of weeks or if you notice the system not acting as it should boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

I strongly agree with the above replies. To elaborate a bit more, CleanMyMac (and similar apps) tend to 'find free space' by clearing (read: deleting) important system files that may not become apparent until the next update. If you haven't used the cleaning function at all, you may be fine- but if you have, a worst case scenario would include reinstalling macOS.

Mac doesn't need virus scanners- the built-in security is just fine and perfectly sufficient.

Protecting against malware in macOS - Apple Support

To add to the excellent advise already supplied --- >

Certain Applications maybe available on the Apple Apps Store - this only means the Developer is prepared to pay Apple a portion on each sale. What the Application may do to the computer is up to the User to check this out before purchase

Any of the below should be removed as per Developers Instructions 

This will include CleanMyMac 

Caution: even after removing CMM - the damages it may have inflicted on the OS may or may not require Reinstalling the OS to undo the damages this specific Application has caused

As written above, Safe Mode. It's a great way to perform general maintenance on your computer.

Start up your Mac in safe mode - Apple Support

You can also find the app caches in ~/Library/Caches if necessary (may be hidden).

Do not use third party apps like CleanMyMac or any other third party app that claims to protect, clean, manage, boost performance, etc.. It does not matter if you are a photographer or anything else.

Another poster reported that CleanMyMac deleted an entire Photo library. No third-party application know the "current" (whichever sub-version you have installed) MacOS system files better than Apple.

Hollasue wrote:

So what do you recommend for cleaning up caches and files?

Let the MacOS do its job. It is very good at managing memory and clearing cache.

Try it, you might be pleasantly surprised at how well your computer performs without these unnecessary third party apps.

A restart in Safe Mode. This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and font

When checking the Activity Monitor, select the Memory tab and sort by RAM usage. It is highly likely that the issue being reported is actually being caused by the app you are using.

Get rid of CleanMyMac, it is known to cause problems with Macs and isn't needed. This may resolve your Ram issue and other potential problems.

In addition to Mal-S's very excellent advice, also get rid of VShield.

And, every once in a while, close all the open Facebook windows. It's a known memory hog.