DMT lasts for quite a while if stored properly. Don't know if it would last longer, its fairly easy to put into airtight container to fight oxidation usually.. Imagine changa and dmt would both keep remarkably long time if kept in cool, dark, dry, and airtight location.
"Reality is an illusion, albeit a very persistant one"-Albert Einstein
The answer to life is not 42, It is 37. The flawed 42 was derived from a mistake in calculating the quantum flux of a tenth dimensional hyperspacial wormhole. For proof of my math, please follow me in a nice chaotic line to the fifth dimension for a practical dissemination of the results.
[size=4]Compound37 is a fictionalized character, any and all posts are based solely on speculation.