How often your dryer vent needs to be cleaned depends on a few of the following elements:

• Number of people using the dryer
• Pets in the home
• Type of dryer vent line, for example the more flexible the line the more ribs to catch and hold lint
• Structural design of the piping system; including length, number of bends and direction of piping.

Overall, the heavier the usage or the more complex your system, the more frequently it will require cleanings.