Maybe it´s individual and you will enjoy this kind of work for long years :) I did it for like 3 years. Same before that with translations. I did mostly movies and TV documentaries so there was a great room for creativity (unlike with translating contracts, manuals and other boring technical stuff) but again, after some 3 years, I didn´t find it that cool anymore. Here on Hive though, I am already past that 3 year milestone and still enjoying it so hopefully, that´s something I will never get tired of :)
Heh, no surprise about 
RE: How Quitting From Freelancing Sites Made Me A Better Freelancer