I learned that if we are referring to money in general, then we don't use "the".

So: "I need money" = I need money in general (any money).

But when watching a movie, I heard people say "I need **the** money".

Here is the plot - a girl is currently out of job and she came to a job interview:

> 
> **Interviewer**: "Why do you want this job?"
> 
> 
> **Girl**: "I need the money."
> 
> 
> 

So, I think maybe her sentence is implied and its complete sentence could be: 

> 
> "I need the money **to support my lifestyle**."
> 
> 
> 

So, when should we use "**I need money**." and when should we instead use "**I need the money**."?