As bhollar has said in the past, “nothing lasts forever”. So, was doing some wondering this morn...I have a 6” SS insulated forever flex liner. Just had it recently inspected, after about 7 years of use. Sweep said it looks good. I hit it twice a season with the sooteater, and to my Knowledge never haD a Chimney fire. Just curious from the pros who do this for a living, and the veteran burners...what’s the realistic life span of these things? In general. I know there are a ton of variables, but just wondering when I should be planning on a replacement. 10 years? 20 years? Your thoughts are appreciated. Thanks.