I take the view that leaving things switched on overnight or when otherwise not needed is wasteful and a potential fire hazard. Therefore I have always unplugged the router when not in use but then TalkTalk made "improvements to the service". When I contacted them to report drop-outs and very slow broadband much of the time when it was live, the outcome was that their "new, improved" system requires the router to be on constantly and uninterrupted, otherwise the system thinks there is a fault and it defaults to slow or nil broadband. Are you perhaps experiencing the same thing ? I do not know the situation with other UK providers but I might add that I regularly use internet facilities in other countries and nowhere have I come across TalkTalk's type of requirement.