Our lovely dog is almost 9 months old. He's quite reliable with regards housetraining, but if we don't notice he needs to go out, he'll take him off somewhere and wee.
Our older dog starts pacing/woofing if he wants to go out. This dog...nada. Nothing. The only way I know is that if he is sleeping and gets up, he needs to go out.
At night time, he usually sleeps through, but occasionally he gets up off the bed, and wanders out into the hallway. If we don't suss it (wake up!) then he'll relieve himself.
He's a quiet dog, rarely barks, etc., so how do you teach them to alert you?