I find the vocabulary isn't that hard to learn as you pick up new words each day and eventually they stick. The grammar required to put those words together is another matter though.
It really does depend on your situation though. I have one to one lessons twice a week but it's not really enough as I manage to get by without having to speak that much during the week.
However, I know people who have picked it up fairly quickly because they are working in a public facing environment where they really have to learn fast.
The grammar required to put those words together is another matter though.
I wrote down a grammar card with all the verb conjugations (-AR, -IR, -ER verbs) and carried it in my pocket everywhere. When I couldn't remember, I (as soon as practical) pulled it out of my pocket and double-checked.
The most difficult one for me was getting la/el correct. Although by that point I knew the correct gender of each noun, it didn't come out correctly when speaking quickly.
It really does depend on your situation though. I have one to one lessons twice a week but it's not really enough as I manage to get by without having to speak that much during the week.
However, I know people who have picked it up fairly quickly because they are working in a public facing environment where they really have to learn fast.