As a general rule of thumb, it is best to allow the wax to melt from edge to edge of the container, especially on the first burn. This will prevent the tunneling effect and allow for a smooth burn through the life of the candle.
With Āfire Candles, this will take approximately two hours.
In candle world, burning a candle for more than 4 hours is considered an abusive burn. Abusive burns shorten the span of the candle and can lead to over heating of the container.