Regular Sweeping

The severity and density of residue in a chimney will vary depending on many factors most obviously the choice of fuel, frequency of use, location, installation etc.
NACS recommends sweeping as often as every 3 months, depending on the type of fire/fuel. This will help reduce the risk of fire and carbon monoxide poisoning, help maintain the efficiency of your appliance and probably the life of stainless steel liners.
NACS recommends the following frequency of sweeping:

• Chimneys with woodburning appliances – quarterly when in use;
• Chimneys with solid fuel appliances:
  • Smokeless fuels - at least once a year;
  • Domestic bituminous coal – at least twice a year;
• Chimneys with gas/oil appliances – once a year;

These are recommendations only and I will always advise you if I feel your circumstances should vary. It is important to check the wording of your home insurance policy as some companies have their own particular requirements, especially if you own a thatched property.