Re measuring power, varies: power meter plug, usb device, multi-meter. See pic - 2.3W in halt, it seems to vary. Found that cheap power meter plugs are easy to use and accurate enough. Of course, with Pi 5 the consumption is nicely indicated by the warm glow from the underside! - for me, an engineering problem that should have been sorted pre-production.
Just to say, I’ve had V1 B+ models as media server and house BMS running for 10 years, no problems. Also have a 3 B+ with a camera in a jar underwater in a pond which has been running for 2 years! I do like my Raspberry Pis but not the 4 and less so the 5 - can’t see the point (not powerful enough to run a pc / not efficient enough for 24/7 365 projects).
