This is causing me marital problems too.
DS can be soooo defiant, esp. with his Daddy. If you wan't him to do anything, you have to ask, and ask, and tell and tell, and even then he might not do it.
I have always worked on rewarding good behaviour, we do treats, star charts, pocket money jar, the lot but we still get days of non-co operation.
I do take money out of the jar for bad behaviour, and send to room for timeouts, but dh says ds sees us as a soft touch.
I went out shopping for 2 hour yesterday, and came back to a house of war, cos ds had been putting his feet on the desk while using my computer, and dh had to physically carry him away from the computer to stop him. Dh argues with him too.
Dh and I have had a major row today (another thread on this), cos dh thought ds shouldn't go swimming today, cos of this yesterday.
How do you get a bright, intelligent boy to co operate more than 20% of the time.