When a candle keeps going out, there can be several causes. These include wick issues, difficult to ignite wax or a poorly designed wick, drafts or hot spots in the burning vessel, moisture and other things that disrupt the quality of fuel for the flame. It could also be a matter of spiritual significance for those who use candles as part of religious or spiritual practices.
In most cases when a candle keeps going out, it means that the wick is too long and needs to be trimmed. This can easily be done using wire cutters or nail scissors. If you use wooden wicks, this is particularly important as they can have knots that interfere with the capillary action of the wick.
Another common issue is tunneling, where the molten wax around the wick burns down to the bottom of the melt pool and drowns the wick. This is most often a result of burning your candle too short, or by placing it in an area with drafts or other factors that interrupt the flow of fuel for the flame.
It is best to let your candle reach a full melt pool each time you light it. This will ensure that you are getting the most from your candle’s burn and that it will last longer.