I have five data drops to install for a resi home in the rough in stage. How do i support the cat 5 as i hear its not a good idea to lay it on the rafters and how do we support the vertical runs.

Follow simular rules of support and protection as you would for romex.

If you lay it on rafters in an accessable attic, some guy is going to have to crawl over them some day. (Get them caught in thier linemans as they shift by... Snip!)

An OK method of support in wood framing is to drive a romex staple 3/4's in, and loosly zip tie the cables to it.

For larger bundles that you might want to re-pull or add to later use dry rings, (Bridal rings) or J-hooks and leave a string. If you set up rings in way that the angle of attack at each is 30+/-degrees, you can pull more later most often.

Support with this stuff is more guidance than anything.

For vertical drops over 20' you should strain relief it by zip ties snuggly, but not too tight as to deform the jackets. Just enough to support the wieght of the cables.

For what it's worth, those are the same methods I have seen data guys employ in houses I have worked on.... if you were looking for a second opinion.. the advice is sound.