In addition to the auto function that works great, the auto/on/off switch was a game changer for me. I can't believe I've worked wood for 4 years without this. Turning the two-stage separator on when I'm sanding or using a carpentry machine, and then turning it off after 7 seconds without having to bend under the workbench to turn it on/off might have saved me a few seconds, but the effect is great. Switching from automatic to one-on-one is essential if you need to use a vacuum to vacuum in preparation for rework when you don't have a tool connected.