We’ve just had a a lot of electrical work done and plastering.
In contrast to the majority opinion, we didn’t run Cat5 everywhere, it’s our house not an office block, what possible need to I have for a router in the bedroom? Just plugged power line adapters in the rooms where wi-fi was an issue.
More plugs than you need though. And ones with USB sockets in the likely places (behind the TV for the chromecast, in the kitchen for charging phones)
And if you want the modern, hidden screws, almost flush fitting sockets, spec them first, because they’re a PITA to fit into back boaxs which were intended for cheap plastic sockets unless your electrician took an unreasonable degree of price in his work those white sockets cover a multitude of sins.
Surround speaker cabling would be nice, although after we finished we spun the living room round 90deg, so it requires a degree of commitment to the interior design.
The one thing I regret is not moving the phone socket. It would make more sense to have the router hidden away somewhere, not on the side table in the study where the phone would have been 10 years ago.