A couple of weeks ago a young mother and child were killed in a house fire in our community and the fire began in the laundry room. I did not hear the exact cause but it prompted me to remind those that have dryers to make sure your dryer hose is cleaned of lint regularly. I do know someone personally that had a dryer fire cause by lint build up. More than 15,000 fires a year are caused started by the dryer.
Twice a year would be what I consider minimum for cleaning your hose and it would really depend on how much you use your dryer. Flexible hose should be cleaned more often as there are more areas to catch the lint.
It is recommended that the dryer hose be made of aluminum either flexible or non. My hose is made of flexible aluminum and is easier to hook up from the dryer to the outside vent. Mine also has a flexible ring to attach and re-attach to the dryer and vent. There is also a band type that uses a screw but I found that harder to remove and attach. Please be sure and shut off the electricity or gas before cleaning your dryer.
Please keep yourself and family safe by making sure the dryer is free of lint build up.