In order to target this level of buildup annual cleanings are preferred for most people. If your vent system is DIY-friendly (only exhausts a few inches through the side of your house and does not require an extension ladder to access), then by all means clean your vent system more regularly. However, for professional cleanings it usually turns out that an annual cleaning does pretty well in targeting the desired level of accumulation. If you go beyond this level you begin to flirt with the fire-hazard aspect of your vent system. In order to incentivize this proper maintenance we give an annual cleaning discount and offer, for a further discount, to schedule your next appointment a year in advance.