Ahhh, coffee roasters in teh south, I live in Minnesota and I have to clean the chimney for the wood stove almost as often as the chimney for the roaster. They make really nice chimney cleaning rods and brushes, if you get the fiberglass rods, beware they will give you invisible splinters, hurt like hell.
Also, be careful not to accidentally unscrew the rods while cleaning out the pipe, they would be really hard to extract from there.
On our roaster we clean the pipes out once a month, but ti will depend on the size of roaster, and the amount of coffee you roast. In a warmer climate you may not have as many issues with teh smoke congealing on teh insides of the pipes also.
As for what they have where I work we have a 60k simiac with afterburner, cold chaff and hot chaff collectors, we have a maintance schedule and stick with it.