never drill from outside,,its easier to repaire outside than plaster inside
Not always true, surely pebble dash or old brick faces are more likley to pop than soft, sound plaster? Also outside in implies less dust in the house.
so how do we test from outside for cables or pipe work,,i have been in the satellite buisness for 20 years ,and now am a team manager for one of the largest satellite /aerial company in the uk .and if one of our engineers drilled frrom outside in they would be in trouble if they hit a cable or pipe
ok all our engineers are trained not to drill from outside in,simply because you can not check with any type of detector through a wall that is between 12in ans 3 ft thick!..most customers want the coax coming through the wall where all the face plates are i;e existing aerial socket and power sockets to keep neat,so it would be very dangerous to drill from the outside in
Your last point is valid but it isn't implied by your previous point.
I would be concerned about anyone drilling without checking both sides before hand!!!