How do you know when to use ''için'' or ''niçin'' in Turkish?

In Turkish, ''için'' and ''niçin'' are two important words that are often used in different contexts. Both of these words are prepositions and have different meanings.

''İçin'' generally translates to ''for'' or ''to'' in English. It is used to indicate a purpose, reason, or goal for something. For example, ''Benim için bir kahve alır mısın?'' (Can you get me a coffee, for me?). Here, ''için'' indicates the purpose of getting coffee for the speaker.

On the other hand, ''niçin'' is a question word that means ''why'' or ''for what reason''. It is used to ask for the reason or purpose of something. For example, ''Niçin buradasın?'' (Why are you here?). Here, ''niçin'' is used to ask the reason for the person's presence.

So, to summarize, ''için'' is used to indicate the purpose of something, while ''niçin'' is used to ask for the reason or purpose of something.