After weeks of planning, days of packing and hours of travel, you’re finally relaxing on vacation — swearing you’re not going to worry about life back home. But inevitably, one thought creeps into your mind: “Did I leave the stove on?” Maybe it’s the hair straightener, or leaving the garage door open, or even locking the front door. Whatever plagues your peacefulness, Lifehacker shares this genius tip: Use your smartphone to snap a shot of your stove dials (or whatever it is you worry about most) before you head out the door. Make it a part of your usual pre-travel routine. That’s it. It’s so simple, but such a small step can save you from feeling stressed ever again when you’re away from home. If you’re lounging on the beach and anxiety about the little things back home start to pop up, whip out your smart phone and put your mind at…