The season is barely underway and I just swept my chimney. Yeh already and it was the worst I've ever seen. Easy 1/2" to 3/4" of it for a loss of an inch or more of pipe diameter. Here is the kicker, 50% of what I burn is 3yr old splits and the other half has been kiln dried cabinet lumber scraps. IMO best , driest possible fuel I could burn. It was just the dry flaky kind but jeeze, how can any stove be this bad. Never before has it built up so fast. Specs are 35' class A stainless on top of 6' of black stove pipe. I tap daily on the stove pipe with a broom handle and I knew it was bad from the dull thud it was making.