The charcoal and frankincense are an offering when you are starting your conjure, you can snuff the candle and conjure again and agin until it’s finished or you can burn it continuously
Every time you light the conjure candle is when you light the charcoal and add the frankincense. If you only light your conjure candle once then you only light the charcoal once. If you have to snuff the candle out when you relight the conjure candle you have to do everything all over again. That includes cleansing, chanting, changing of the glass of water, praying and lighting of the charcoal and adding the frankincense.
I do mine for 6 hours at a time. Weekly on its day.
The charcoal and frankincense are an offering when you are starting your conjure, you can snuff the candle and conjure again and agin until it’s finished or you can burn it continuously