Have been for around 7 years, local wife, watch my wife watching local television, some local friends, went studying Cantonese... still don't get it :-)!
You learn a lot in the beginning, and then you forget the words one by one over the years... The main problem is, that you cannot read or write it, so you cannot learn it passively, unlike any western languages.
Better focus on improving your English (if you're not native)!