When I buy tins of tobacco I leave it in their original tins, put it in a cool dark place and never open one unless I plan on smoking it. All of my bulk tobacco gets put in it's jar and I never touch that until I am ready to smoke it. I keep my tobacco at the same temp and amount of humidity and never open anything until I plan on smoking it. I have never had a tin or jar fail no matter what shape the tin is or what type of jar I use. I have never had any mold either. I don't use mylar or foodsaver bags and all is good. I hear people complain about failing tins or mold but have never seen it myself. I don't know why that stuff happens as I am no scientist and I know I cannot be the old person who has never had issues. I have seen a couple of GL Pease Navigator tins bulge but the tobacco was perfect each time it happened which was only twice. The Navigator tins were both from 2012 when it first came out.