Not any more then unplugging them or using a wall switch.
While it is true that electronics are more prone to failure at the time of what is known as in-rush current, basically something was already on its way to breaking, just takes that last little bit to break it. In rush current is when the capacitors are well drained in a power supply or other circuit. When they first turn they draw more current then at run time.
Per a mandate in the UK, all new devices must consume less then 1W on standby. They don't make separate models for UK vs the US. Most electronics beat this by a wide margin. (I would have to double check when this was put in place, but it has been a long time)
Your modem and router will consume a little more since they...