Monster iPhone – Everything iPhone

I've been trying to figure out how long I should be making my personal ringtones for my iphone. I know when you buy them, they're 30 seconds, but it almost seems like once the ringtone is done playing, it goes once more, until the phone stops ringing. I want my ringtones to last the whole call, and not repeat themselves. Anyways, I've been making them 40 sec. long with a 10 sec. fadeout. Any advice is appreciated.

30 sec