I have a high ceiling, with a long 6" flu on a free-standing Avalon wood stove that was new when my house was built in 1994. I recently had the chimney cleaned, and the chimney sweep (new to me, other one retired) wrote: "Top chimney section is slightly disconnected from coupler. Chimney is nearing end of expected life span. Suggest replacement. Estimate $4K-$6K." My gut feeling is to hire another chimney sweep (even though the chimney is clean) and get another opinion. Even if this is necessary, does $4K-$6K make sense???? I have never had any leakage or indication that anything is out of the ordinary. I would greatly appreciate any comments. Thank you.