It cost me $3000 to have a professional run 7 CAT6 cables to every room throughout my 80 yo house, plus one to the modem, along with wiring proper earthed power into another four locations or so. The man was not claustrophobic. Plus less than $500 for another contractor to fill in and paint the sheetrock that was required in storage rooms. The cables meet in the basement in a server rack.

It was well worth it to me. I have teenagers and everyone has an Eero in their room, plus hardwire for the home theater and office.