What will the rooms be used for? Will you (ever) need phone, cable, ethernet? Put them in now if you can, and leave several runs of string or thin rope in conduit for pulling cables later.
One room will be a nursery (first born is expected in april) second room will be an office/ what ever room. Literally the two rooms we have now never get used or entered. They both have cable ran into them already as for internet I do installs of video and security systems so I pull cat 5 wire every day so I'm not that worried about it plus I have wifi in the house.