Share with you guys this post by a friend... Very true indeed.
It's a challenge to maintain one's fluency in Japanese outside of Japan. Recently, I've finished reading "Polyglot: How I Learn Languages"by Kato Lomb, "a Hungarian interpreter, translator, language genius and one of the first simultaneous interpreters of the world" (courtesy of Wikipedia).
She introduced the concept of "linguistic microclimate" which is "the linguistic environment which immediately surrounds you in your studies and which you can, to an extent, create for yourself, even in your home". This is exactly what Khatzumoto of the "All Japanese All The Time" blog created for himself to became fluent in Japanese before stepping onto Japan soil.
In Singapore, it's very difficult to maintain one's fluency unless one is using Japanese actively on the job or in social circles where there is frequent contact with Japanese people, so the onus is on oneself to create a "linguistic microclimate". Examples include watching Japanese dramas, listening to Japanese songs, reading Japanese books, surfing websites in Japanese, etc. As one's fluency drops drastically when not using the language, how well one's fluency is maintained is directly proportional to the contact time one has with Japanese.
In my office, there's a guy, Mr. D, who is a Singaporean. As those who are familiar with a typical Japanese office layout will know, the director's table is beside the window and the next senior person's table will be facing the director's table. The less senior person's table faces the next senior person's table in a column, etc.
When I first joined my company, I was a bit surprised when I first heard Mr. D speak Japanese, as his fluency is no different from that of a native Japanese, which is quite rare in Singapore. As my cubicle was near both Mr. D and his Japanese director's tables, I was able to hear their conversations. The more I listened, the more I was impressed with Mr. D's fluency. However, I didn't have a chance to talk to him although we recognised each other.
This week, I met him at a staircase and I asked him whether he had lived in Japan. He replied "6 years". I then complimented him on his Japanese and he dismissed it modestly.
From this, I can conclude that the best way to maintain one's fluency, in the absence of a Japanese spouse/boyfriend/girlfriend or good Japanese friends, is still using Japanese in one's job. Also, I think a precondition is that one's fluency level should be very near or equal to that of a native Japanese, otherwise the drop will be very steep once one is no longer in a purely Japanese-speaking environment.