Discontinue use of a candle when ½” of wax remains at the bottom of the jar. This will prevent possible heat damage to the counter/surface or container itself. The glass can get hot on the bottom as the flame nears the base of the jar and most of the wax has been consumed. By following this instruction, the glass will not get too hot. It is for this same reason that Yankee Candle does not endorse the use of heating surfaces or “candle warmers.”
Always burn candles well away from drafts, other heat sources, and anything flammable. Make sure burning candles are out of reach of children and pets. Never leave a burning candle unattended.
Some people like to blow a candle out, but this can send wax and possibly embers flying. Using water to put out a candle is even worse. The mixture of cold water and hot wax can send the wax splattering everywhere, possibly leading to burns. The cold water can also be dangerous to glass candle holders, as the sudden drop in temperature can cause the glass to crack, potentially spilling hot wax everywhere. A candle snufferstarves the flame of oxygen, ensuring that it goes out gently, without giving the wax a chance to spatter. It is the safest way to douse a candle without worrying about spatter or burning one's fingers on the wick.
It is a simple rule for anything that burns; fires should never be left unattended. This is particularly true of candles, as some can easily tip over, greatly increasing the chance of fire. The presence of pets just adds to the danger. Seconds matter when it comes to fire, and unattended fires mean that there is not one present to take action in the most important seconds. It simply is not worth the risk.
It is a common misconception that because people often used candles for light before electricity they should be the first thing to turn to for light when the power goes out. Sadly, this is not the case. Candles were only one of many lighting options used before the proliferation of the electric light, and oil lamps were much more common. In most cases, a flashlight is a much better and safer option when the power is out than a candle. This is especially important when rummaging in a closet, as the flame can catch clothing on fire, turning the minor inconvenience of a power outage into a major disaster.