Originally Posted by Pirates Armada
It's kinda like that cabin fever syndrome
That's it eaxctly. It's just not good for the individual to be in Antarctica for too long. As most people don't want to go down for too long and the change over of base personnel happens to this timetable, it wouldn't be good for the base dynamic to have someone who had been there for years and years.
There are many people who go to the American bases - especially McMurdo for just 6 months as there is a very high population (relatively) for an Antarctic base, so I guess lots of short-term people don't upset the dynamic too much.
Other bases have people who are summer-only in when the winter ends and out when it starts - about 2-6 months depending on where the base is. There are winterers (winterovers) who spend a winter and least one, more likely two summers or people do two winters and two or three summers. Time is counted by the seasons rather than being specified by months.
As for who has spent the longest the "World Record" as John says, the longest I'm aware of is three years which several people have done, there's a thread about it here:
I did read once about a sealer in the 1800's who spent around 27 years on the sub-Antarctic MacQuarie Island - think that's unlikely to be broken!
(Pirates - unfortunately the main site search and forum search are separate, so you have to do one on each to look through the whole site