I have been studying Japanese for 4 years, almost every day. I spent the first year on my own, then I went into a private school (which I'm still apart of)and took Japanese as a minor for 2 years in University, I carried on learning by myself though, by having language partners and some private tutors. Its only been 4 years but it has felt like an eternity.
There have been many times where I feel like I'm not really getting anywhere or feel down after trying to read Japanese articles online only to find I didn't know 10 of the 12 words that were being used in the first sentence. It hurts, because I know I put alot of energy into it, but this is how someone described to me learning something:
"Your in a room full of pictures, you spend years learning everything you can about these pictures, you know everything about these pictures down to the last detail. Your pleased with yourself, your happy, then one day you notice something, something very small, something you didn't notice before, its in-between two pictures, you go towards it and discover a door, you open it and find yourself in a room full of new pictures...".
I've gotten to a point where I can read some mangas in Japanese, can get the jist of whats going on in a news story in Japanese, but its no where near enough. The more you learn, the more you understand how much further you have to go. That's just how it is and I'm having a good time going through it all.