Looped Music

Hi,People!

I want to load some songs but they are in loop form(about 8-16 bars repeating again and again).
Can I Use this songs?
If Yes , How many bars I must rendering? Just parts that are not repeated?
If - just parts that are not repeated, I must use clean,not repeated parts without Fade In/Out with beggining of this part or
I can use Fade In/Out with repeating parts?

I suggest you make a Music Kit.