“Learn” is like “fluent”—it’s an ill-defined word. If you “learn piano,” does that mean you can read music? Do you know the name of each key? Can you play relatively simple songs? Can you play new songs after reading them? After just hearing them? Can you play Beethoven flawlessly? Is your flawless performance consistent? Can you breathe underwater?

Geez. Overkill.

"Learning" a kanji could include mastering any or all of the following...

1. Meaning: When you see 年, you know that it means “year.”
2. Reading (in words): When you see a sentence like もう年だなあ (mou toshi da naa), you know that 年, in this context, is pronounced toshi. (By the way, this phrase means “I’m getting old.” Use it when you forget something, make a stupid mistake, etc.) Similarly, when you see a word like 去年 (kyonen, “last year”), you know that the 年, in this word (i.e. this context), is pronounced nen.
3. Writing: So when you see 年, you are able to write it like this:
4. Reading (independent of words): Above, we said that 年 is sometimes pronounced toshi and sometimes pronounced nen. These are called kunyomi and onyomi, respectively.

Now I’m gonna say the controversial stuff that gets me in trouble:

First, you never need to study the readings of kanji independent of specific vocabulary words. That is, you NEVER need to study kunyomi or onyomi. I think this is an even bigger waste of time than learning kanji by rote memorization (=hoping to magically learn a kanji by writing it 10,000 times in a row). Seriously. Memorizing the readings of kanji is a waste of time. Don’t do it... unless you’re learning the readings through learning actual Japanese words.

Studying writing is optional. Some people really enjoy it. There’s something thrilling about putting pen to paper and spelling out these weird and exotic characters. If you enjoy it, then go for it. Personally, I never studied the writing of characters (although I used to write them with my fingers when reviewing).

#1 and #2, however, are absolutely mandatory. We must be able to recognize kanji, and we must be able to pronounce them accurately as they appear in various words and phrases. (Don’t freak out; this will happen naturally over time.)

In the Hacking Japanese Supercourse, we jump-start our studies with a 97-day sprint through the meanings of the kanji only (#1 above), then we learn the readings through systematic vocab acquisition. Some people don't like learning kanji this way, though, and in such cases I recommend just (1) learning lots of vocab and (2) forcing yourself to use and read kanji when studying. Over time, you can integrate kanji into your "sight vocabulary," which I talk about in this article.