My wife gives me a present every year on my birthday which is in june. I get a chimney brush in one hand and a ladder in the other.
Our brush is on flex rod and I just run it down from the top after removing the China hat. All the smug goes into the stove above the catalytic combustor . I made a attachment for my shop vac that sucks all the fumunda out.
Short answer,,, once a year.

the consolidation of the states into one vast republic, sure to be aggressive abroad and despotic at home, will be the certain precursor of that ruin which has overwhelmed all those that have preceded. Robert E Lee
~Molɔ̀ːn Labé Skýla~