hello there.
It depends on the language... as for English, I didn't need any reason or any specific goal to start it. Or maybe the reason was so apparent that I didn't need to even think about it...when I was younger, I wanted to educate abroad and then start a living there...but I gave up.... as for other languages,... let's see..
Japanese: I learned it because I liked it... but after 3 years when I got fully familiar with Japanese culture, I figured out that I never want to even visit Japan, so just dropped it.
Arabic: I had to learn it, was required by my university.
Turkish: My father forced me to learn it, but after 2 years, I started liking it and then continued on my own.
Russian: I still have no answer :D
how many hours I dedicate for language learning... at least one hour a day... less than that isn't called language learning, it is more like playing with a language or... just entertaining yourself with it as a hobby.
Goal level of proficiency... mainly being able to communicate freely, without any language barrier, but never any academic stuff on the horizon ... not because it's not interesting, but too far to be real.