E-liquid is thinner than you think, especially in warm conditions. If a disposable sits in a hot car, the liquid expands and can push past the seals. That's when you get that annoying gurgling sound or a wet mouthful of juice. It's not dangerous, but it's unpleasant, and it's the most common reason people think their device is broken when it's actually just overheated.

Heat also affects the battery. Most disposables use a lithium-ion cell, and extreme heat can degrade its lifespan or cause swelling. Keep your vape out of direct sunlight and away from radiators. If you're carrying it in your pocket, body heat is usually fine, but don't leave it in a parked car in summer.

On the flip side, cold can cause condensation inside the device. If you've just brought a disposable in from freezing temperatures, let it warm up to room temperature before using it. Otherwise, you might get weak hits or a slightly flooded coil.