I watched an instructional video the other day where the guy kept palming his gauge manifold and CRANKING down on the valves when he closed them. I've seen techs use channel locks—and even vise grips—to tighten down their gauges “just in case” when they have a hard time finding a leak or a vacuum that won't pull down.

Seriously… No. Stop. Please.

Gauge manifold valves can be tightened and loosened with your fingers; you don't need to crank down on them. When you do, you can ruin the seals. Then, you really will need to overtighten them every time.

If your gauge seals need to be replaced, then get new seals and replace them. However, being a bit more gentle when opening and closing, storing them more carefully, and even putting a drop of refrigerant oil on the seals from time to time will keep them working for a long time.

Especially with modern digital gauges (like my favorite, the Testo 550), you are making a big investment. Treat them well.

Finger tight only.

—Bryan