ADSL Router

[#1]

I visited my brother yesterday who told me he switched of his BT Voyager router each night to save power.
He has been doing this for 12+ months.
I was always led to believe if the router stopped handshaking with the server, it would register this as a fault and reduce the line speed to its lowest level in the hope of restoring the connection.
However, trawling "Google" it seems everyone powers it down when not in use.
So who is correct ?

[#2]

If you power down over night so it's just switched off once a day then you shouldn't be much of an issue.
It's switching off / on many times a day that could lead the exchange equipment to think there is a fault.