We do this every night. Stick with it. Even now, months into the rule we still have smuggled devices (accidentally

) being left in bedrooms - it's so wearing. It really stretches out bedtime.
It's not foolproof as we've come down in the morning and found phones missing from plugs - obviously retrieved during the night or even at 5 in the morning one sleepy teen told me
We've just recently found out how to turn off the Wifi for individual devices which has helped a lot. Via the BT hub - it has done away with many arguments as they only converse via Snapchat or Insta....texting is lame don't you know!
The older teen has his Wifi on for 30 mins longer than the younger.
It doesn't help with downloaded games etc on tablets but it has been a big help for us.