We don't turn ours off at any time, but we use it (when we are in) to "vet" calls and pick up when we want to - otherwise they can just leave a message!!
Agree.
People also have showers, baths, play loud music, sleep, vaccum, go in the garden, entertain, use a sun bed.
Whether it is 1985, or 2013, why turn an answering machine off when at home ?