Originally posted by Xenoc
Wow. That is incredibly extreme usage... It does attest to the fact that it probably isn't damaging in any acutely physical sense, but the fact that it has caused any lasting changes in your mental functioning, even if they are only apparent during sleep, implies that 2c-i has some potential for psychological damage. What you interpret to be positive or neutral (crazy dreams/improved dream recollection) could be considered quite negative by others...
...Regardless, 2c-i seems to be one of the more frequently complained about 2c chems as far as side-effects goes... I have heard complaints of extreme headaches, symptoms that potentially implied kidney complications, and there are numerous threads on 2c-i and HPPD on bluelight if you search for them. Common sense dictates that a drug with so many complaints, even if some people don't experience all of them, isn't "harmless".
But, all of that being said, to answer the original question- 20mgs every 2 months or so is unlikely to cause any acute lasting, physical or mental repercussions.