Most Helpful Girl
When you don't think about her as often as you and other women creep into your thoughts more and more.
When you find that her opinions/thoughts go right over your head and you just don't give a damn anymore.
It becomes effort to have sex with her or share intimacy.
When you look at her and realise that she is not that special anymore.
A bad girlfriend is someone who only wants you for either status, money, sex, just having a man by her side, doesn't respect you, your friends or family, is selfish and everything is about her, will only be affectionate/intimate with you when she feels like it, will put you down or manipulate your emotions to get her way.
Most Helpful Guy
its time to break up if you've lost interest , no longer respect her or sense she doesn't respect you , you'd rather be doing other things than spend time with her. or you've meet someone else who is a better fit and would rather date them. its not that she's a " bad gf" its more things just aren't meant to be , its not a relationship that is going to last forever