Whether you spend $1 or $100 on a scented candle, a few tricks can make them last longer. First, freeze candles overnight before lighting them; the cold wax will burn more slowly. Be sure to keep the wicks trimmed to about ½ cm, too. Not only will this help the candle burn evenly, it also reduces the amount of soot and smoke in the air. Finally, if you've finished a large pillar candle, there's no need to throw it away. Just drop a votive in the hollow part. The scent will be gone, but the flickering ambiance will remain.