24 by 24 deck with roof how far apart 4x4 posts need to be. This will be screened in above 3 feet and floor will be complete not spaced boards but will be treated and the posts will be about 4 feet deep and concreted in

How high off the ground will the deck be? If they are short, I'd use 6X6 on poured footing blocks with steel pins to hold them. My deck is 12" off the ground and 6X6 are 4ft. Apart.

Do u have a girder supporting the deck? If u do, the size of girder will determine how many posts u need for support.

On a 24' span u would need 2 girders. One at mid span and another approx 1' from outside edge. My deck has 2x12 girder and 3 posts for support. The smaller the girder the more posts u need.

Chuck

Me personally, I would be going with 6x6 on 6ft center's

Yeah most building codes don't allow 4x4 posts any more.

I would use 6x6's also and instead of putting them in the ground(really wasted material and it will rot) place the 6x6's on 12" poured Sono tube bases 4 feet deep.