What do you do when a candle doesn't burn out in a spell?

Candles are a common component of many spells and rituals.

If the candle is a spell candle with a specific single use, you should allow the entire candle to burn out on its own. If you must leave the area, place it somewhere safe and fire proof. I have left candles to burn out in the bathtub (no water in it) when I had to leave.

If the candle is a spell candle, made with the expectation of relighting it, for example a seven-day prosperity spell, the candle is snuffed out, (do not blow it out) at the end of the allotted time of that segment of the spell.

If the candle is part of a ritual, for example: the elemental candles used when calling a dismissing the elements (quarters, directions) then the candle may be snuffed out when you dismiss the elemental.

If the candle is part of a ritual and used to invoke the deities then it should not be put out at the end of the ritual, but allowed to burn out on its own. In the case of large multi-use candles sometimes used for this purpose, you may snuff out the candle when you are dismantling the Altar after the ritual.