Hi @PhillSeacroft,
TalkTalk do generally recommend leaving a modem/router on 24/7, however just switching it off once at the end of the day is not going to do any harm. So do you have a separate router and modem with your package ?
What TalkTalk package do you have (e.g. ADSL, Fibre 35 / 65, Full Fibre etc.)
TalkTalk do carry out automated maintenance overnight, which can occasionally include updating your router to new versions of firmware. So if your router is never on overnight then this could delay you getting these updates, or the updates may happen when you switch the router back on, and could then interrupt you during the working day for a little while.
You need to be careful you don't switch the router off and on too many times during each day, as the Openreach network equipment can detect multiple on/off cycles as a possible fault (if your service is one that comes down an Openreach phone line), and can then start to reduce your speeds to try to stabilise your connection. But that would only usually start to happen if you switch the router on/off more than 5 or so times within a 24 hour period. So if you just switch if off once at the end of the day then that should not be a problem.
