The FSI’s (U.S. Foreign Services Institute) answer to how long it takes to learn Spanish, is based on classroom hours. The problem is, the traditional classroom is one of the least effective ways to learn.
In a group Spanish class, you have one teacher lecturing 20-30 students. In a 3-hour class, each student might only get 10 minutes of actual speaking practice. Also, the class moves only as quickly as the weakest student, so you may find the pace of learning much slower than what you’re capable of.
In contrast, if you’re taking part in 1-on-1 conversation practice, you’ll probably get to speak for 30 minutes of every hour. In a classroom, you can hide in the back and passively listen to a lecture. But when it’s just you and your conversation partner or Spanish teacher, you are actively learning the entire time.
According to research from the NTL Institute, people remember much more information if they are learning it actively:

In other words, if you’re focusing on having conversations (practice doing / immediate use), you could be learning up to 15-18 times more efficiently than in a traditional classroom (lecture).
By concentrating on the most efficient ways to learn Spanish rather than the slow, outdated methods recommended by the FSI, you will be able to learn in a fraction of the time.