Yes. If you run vm_stat in the Terminal, you can see how few pages of RAM are actually left free at any given time. Modern operating systems aggressively cache

Yes. If you run vm_stat in the Terminal, you can see how few pages of RAM are actually left free at any given time. Modern operating systems aggressively cache files in RAM to improve performance. The green/yellow/red graph in the Memory tab of Activity Manager is the best way of seeing if you need more RAM at a glance. In my experience, macOS won't do any swapping in the green. In the yellow, the system is still pretty usable but there's some swapping going on. When it turns red, your SSD will be getting thrashed pretty hard.