It is important to keep in mind cleaning the chimney needs to be carried out regularly. There are good reasons to clean the chimney these include the elimination of soot, debris and any form of obstruction most commonly bird nests. Obstructions in the chimney can mean that the products of combustion which include smoke, fumes and carbon monoxide will not be carried away up the chimney and into the atmosphere. Instead they can be forced back into the rooms of the house causing serious injury or even death. Also when cleaning the chimney you will remove any loose or degraded mortar from the chimney lining which could otherwise fall down into your fireplace.
It is clear from the above there are many reasons to make sure the chimneys are regularly swept as this would not only help with the general maintenance of the property but also help to fulfil your building insurance requirements.