I was pleasantly surprised to find just how nicely a well-tightened Mason jar will preserve pipe tobacco.
I have 9 or 10 jars of various tobacco in Mason jars and they somehow got pushed to the back of the shelf and hidden by books. I was digging around the other day and found them; the stickers on the front said they'd all been closed up in early to mid 2009 and they'd been untouched since then. I opened the jar of Dunhill Light Flake and heard that nice rush of air. The tobacco was in perfect condition, it lit easily, burned perfectly and tasted great! The work involved in keeping cigars in perfect condition for three years would be a little more involved than closing a Mason jar then forgetting about it.
The moral of the story? Buy some 8oz Mason or Ball jars to keep the tobacco from your opened tins in, get some labels (or just use a sharpie on the lid), and label the jars (include the date the tin was opened).