if you have the 5 mg pill (proscar?) then yes you need to cut it to 5 pieces .if cutting it to 5 pieces is too hard you can cut it to 4 pieces as well theres hardly a differnce .
I wouldn't go so far as to say that you should break it into 5 pieces; let's just put it this way: if you want to save some money, then yes, break it into 5 (or 4) pieces.