At six months Pogo and Snarky were at the point where I could leave them loose and not expect to find any puddles upon my return. Chewing couch cushions was another story.. Galen, at 5 1/2 months, is still completely unreliable about housebreaking; I don't expect to be able to leave him unsupervised for several more months.
Annie took a long time to reliably housebreak too - I think it suddenly clicked for her at about 6 months, and about 8 months is when she stopped excited peeing meeting new people or dogs. Confusing matters, we lived with Trixie and her pee pads for several months, and Annie figured that was acceptable for big dogs to use too.
The 8 months was earlier than I was happy with too.... but not crating her = way less separation anxiety (and at that point she was pulling anything in tooth range into her crate to destroy it, crying and howling for hours, and bending the bars on the crate/trying to chew out and rocking the crate across the floor (causing things to be in tooth range). I kept her out of the living room, bathroom, and kitchen, and she had full access to my bedroom and hall (no closet, so also access to all the shoes). Every day for months, I came home, and surreptiously glanced around for something that was destroyed, every day, there was nothing touched, except now and then a sock from the laundry moved onto the bed to snuggle with. I think she was still too uncomfortable and busy waiting for me to destroy anything - but she still got into things occasionally when I was home (toys, laptop cords, USB cables, cardboard boxes, my coat pockets, plastic lids, etc).