Every wall of every room. Every. Wall.

At least 1 wall of each bathroom.

Every ceiling of every room including hallway but not bathrooms.

One wall in every closet including the pantry.

Don’t put the data closet in a crawl space. Put it in a closet.

Run all of the cable in Smurf tunnel to make upgrading/replacing later down the road easier.

This will give you (and the next home owner) the most flexibility in the future. You’ll never have to worry about where the nearest port is regardless of how you arrange each room. Ceiling drops will allow you to ceiling mount WiFi access points.

Pay the extra $$ to have it done now, in the 30 year life of the loan $10k-$15k cost is insignificant.