You never saw any issues, but your systems might have been faster with swap. Even if you're nowhere any threshing threshold, RAM used for caches is better than

You never saw any issues, but your systems might have been faster with swap. Even if you're nowhere any threshing threshold, RAM used for caches is better than RAM used for unused pages, which could have been paged out to swapspace. Note that RAM is much, much more expensive than disk space. If I can sacrifice some of the latter to potentially get some of the former, it's usually a nice trade for me.