How do you pay a fired contractor?

[Ryan Steiner]

Lets say for example you're flipping a house and have decided the project has 5 phases where the GC gets paid upon completion. If they are in between phases and you decide to fire them, do you pay a daily rate for what they had completed? Is it an all or nothing usually? Whats the common practice here? 

Does your contract usually have a clause for non-payment if terms are violated? How do you structure it to protect yourself from a lawsuit or potential issues down the line? 

If I have to fire a GC for not showing up (example), but the rest of the work was done correctly, how do you structure that to pay them for the time they actually performed? I also want to do the right thing while protecting my project.