Another myth:
Swappiness maxes out at 100, and that means it tries to swap everything. Swappiness is a measure of RAM usage.
In reality, swappiness is a comparison between the I/O cost of freeing memory and swapping that data to the swap drive... if you increase swappiness above 100, it'll preferentially swap before it tries 'garbage collection'.
On modern systems, swappiness maxes out at 200.
I'm currently running swappiness at 133, meaning it's approximately 33% more likely to swap excess data than to try to clean it up (and thus potentially having to close programs in a low-memory condition).
I do this because I've got three drives on three USB 3.1 drive interfaces for the swap drives (and all those swap drives have the same priority, so the data will get round-robin written)... I can swap quite fast, so there's less cost to that than closing out a program during a low-memory condition.
If you set swappiness to 100, it's just as likely to swap the data as it is to clean it up.