Eleven years by the clock, but technically more like four years seriously (a year before I moved to Japan and the last three years). I was kind of doing maintenance studying for a few years after I moved back, not getting better but also not losing it. It wasn't until I hired a tutor at the end of 2015 and started playing video games in Japanese and reading a bunch of Japanese twitter and blogs that I actually started really getting better.

My whole play-through-all-of-Zelda-in-Japanese thing only started in 2016, for example.