These are common instructions and good practices for any candle and are meant to prolong a candle’s burn time. A longer wick creates a larger flame, a larger flame melts the wax faster, and the wax melts faster than the wick burns away. So the longer your candle burns, the larger the flame gets, causing your candle to melt faster and faster. Keeping the wick trimmed and burning 4-5 hours at a time slows everything down so you get a longer burn time.

Additionally, burning your candle for 4-5 hours at a time ensures that the wax melts all the way to the edge of the container. The melted wax (not the flame) is what gives off your candle’s scent, so this will maximize your candle’s scent when lit. It will also prevent your candle from “tunneling”, or burning a hole down the center of the candle while leaving a ring of un-melted wax along the inside of the container.