Had over 50 flights on my B400 and belt still looks good. I might change it when i get to around 100. 100 flights deserves a new belt

Having too tight on the belt can cause the belt to tear or shred, tough on the pulley bearings too. As long as when compressing the belt near the gear pulley if they don't reach half way to the other side of the belt its too tight if they touch its too loose they can rub on each other in the boom. Says so on the B400 instruction.

How many flights do you get before the belt goes out?