Good quality candles burn slowly. Cheap candles with high content of parafin will burn faster. Parafin is very dangerous because it burns so easy, it spils and is hard to extint that is why is very important to place a candle into a shallow container before being lit. A really simple way to avoid a catastrophe.
Maximum burn times vary from candle to candle; Follow the manufacturer's instructions (if any). Always extinguish a candle if the flame gets too close to the candle holder or container. For a margin of safety, discontinue burning a candle when 2 inches of wax remains (½ inch if a container candle or jar candle). But still extra care must be excercised. For example never leave the candle near inflamable items or near the edge of the table because a simple movement might knock it off.

Candles generally can be categorized into 11 basic types: tapers, votives, pillars, container(or jar) candles, tealights, liturgical candles, outdoor candles, floating candles, novelty candles, utility candles, and birthday candles.

Alone in the U.S. candle manufacturers offer between 1,000 and 2,000 varieties of candles in their product lines and U.S. retail sales of candles are estimated at approximately $2 billion annually, excluding sales of candle accessories. To manufacture such amount of candles 1 billion pound of wax is necessary. (source National Candle Association)

Finding the right type of candle for your project is a matter of time and patience. Candles sell fast and continuously specially during the dates approaching the holydays, this tells you that planning may be in order. Still your chance of success is feasible. There are more than 400 stablished candle manufacturers in the U.S. without counting the small factory shops nor the people who make candles at home.

Unless a candle has defects that are obvious to the eye, you probably can't tell just by looking if that is a quailty candle. That's why the National Candle Association strongly recommends that you purchase candles from a reputable manufacturer. All NCA members adhere to ASTM candle standards and have pledged their commitment to quality products and practices. Click here for a list of the candle brands names of NCA members.

Here is a good tip from the NCA regarding how to control the smoking of a candle:

A well-made candle will create virtually no smoke when burning properly. However, if the wick becomes too long, or an air current disturbs the flame's teardrop shape, small amounts of unburned carbon particles (soot) will escape from the flame as a visible wisp of smoke. Any candle will soot if the flame is disturbed.

To avoid this, always trim the wick to ¼ inch before every use and be sure to place candles away from drafts, vents or air currents. If a candle continually flickers or smokes, it is not burning properly and should be extinguished. Allow the candle to cool, trim the wick, make sure the area is draft free, then re-light.

There is nothing better than having a peaceful and happy holiday. Candles like other specialty lights are the helpers that bring us joy. We are the responsibles of our well being and safety plays a major role. You can never be completly safe but you can excersise caution and be prepared. Here is a list with a whole lot of safety tips to be safe when dealing with candles. - Special thanks to the NCA.

Photo Credits - National Candle Association (NCA)