The National Fire Protection Association lists the lack of regular cleaning, which leads to creosote build-up in wood-burning devices and their chimneys, as a leading cause of home-heating fires. Because woodstoves have the highest risk of property damage from fires, the NFPA recommends having wood burners inspected annually and cleaned if needed.
Clean More Aggressively
The University of Missouri Extension office recommends you establish a cleaning schedule that eliminates creosote build-up inside the chimney--clean every two weeks to once a year depending on "the amount you use your stove, the type of wood you burn, the type of wood-burning unit you have and the way you operate the unit."
Consult a certified professional chimney sweep for advice on how often your type of wood burner needs to be cleaned based on your personal usage. In general, chimneys for older stoves need to be cleaned more frequently.