Sweeping frequency 
The sweeping frequencies below are for guidance. The frequency will depend on a number of factors including: Type of fuel, appliance used, frequency and duration of use, moisture content of wood fuel, type of chimney. 
I would be able to advise on what’s best for you during my visit and discussing with you your useage, the fuels you burn etc.

Smokeless coals: At least once a year (Often believed to not need cleaning)
Wood: Once a season when in use on open fires, twice a season for stoves. Upto 4 times a year!
Bitumous coal: Twice a year
Oil: Once a year
Gas: Once a year

WoodBurning...

Wood Burns at its best on a bed of ash and requires an air supply from above it, usually supplied via the 'Secondary/Air Wash' air vent.
If you're using a wood only stove (solid base, no grate) always leave a bed of ash about 1" depth in the fire box.
If you have a multi-fuel stove (with a grate) let the ash build up on the grate until it is covered.

When lighting the fire open both top (Secondary) and bottom (Primary) air vents. This will introduce maximum air to get the fire started.
Once the fire is burning nicely, close down the bottom air and then use the top air vent to control the stove. This will also help keep the glass clean (Air Wash).

Solid Fuel Burning...

When using solid fuel (House Coal, Anthracite, Smokeless Fuel) a grate must be used when you are burning solid mineral fuels as they burn hotter and require combustion air from below. On a room-heating appliance such as a Multi-Fuel Stove, the air is supplied via the Primary (bottom) air vent.
The grate allows any ash to fall away from the fire bed and ensures that cool air is available underneath the grate

When lighting a fire in a multi-fuel appliance, open both top (Secondary) and bottom (Primary) air vents. This will introduce maximum air to get the fire started. Once the fire is burning nicely, adjust the bottom (primary) air vent to control the stove, whilst adjusting the top (secondary/airwash) air vent to help keep the glass clean (Air Wash).