13 inch MacBook Pro with Retina Display + Adobe Creative Cloud
It's pretty trivial to open Activity Monitor and look at the RAM usage.

When the graph is in RED - you will have significant slowdowns and really need to take immediate action if you require performance from all the apps running. Usually a restart will let you know if the applications you run have memory leaks and need you to quit them often, log out often, restart the OS often. Or if those apps always use a lot of RAM memory and you should either find more efficient applications to do the same work or run less apps at once or find a Machine with more RAM (assuming your Mac doesn't allow user-upgradeable RAM).

When the graph is in yellow - you're unlikely to be able to measure slow downs, but it's a signal to quit any apps you don't need (email, web browsers with dozens (or more) tabs open, social media, music streaming apps, chat apps (cough slack, cough) and let the system focus all resources to the main apps you need.

When the graph is in green - no worries about RAM being what's causing your workflow to not run at full speed. The constraints you have at that point are network, CPU, or just the apps aren't making use of the machine resources at all and need to be redesigned / updated.)