My Tornado-dog picked up potty training quickly as a young puppy. He caught on to "pee first, then play" with no problem. With poop, he would get distracted and forget because there was so much to do outside. Then he'd come in and suddenly remember "I have to poop"...
As the weather was nice, I could stay out as long as he needed to remember to poop.
Then, when the weather changed, he decided he would rather be inside and he wouldn't pee outside either. And all the waiting in the world didn't get him to poop outside.
So, I started teaching him cues. When he started to pee, I'd say "potty" and when he finished, I'd praise him. When he started to poop, I'd say "poop" and when he finished, we'd go straight inside (that was his reward because that's what he really wanted when it was cold and wet outside) as I praised him.
It took a while with him because he is easily distracted, but one night, we were out back and I was sitting on the patio. He peed and then ran for the back door. I just sat there and said "poop". He looked around, then ran out, pooped, and came racing to the door. I praised him and we went inside.
The next morning, he had the same "aha" moment.
Now, I sometimes have to wait until he focuses (we are learning the "focus" cue - which is simply "stop worrying about the neighbor dogs barking and focus on your goal"). But as soon as he lets go of the distraction, he rushes off to do his poop.
I had to train myself to first understand his poop schedule and then use that as a guideline. My instinct was to have him poop right before bed and when we first get up. But after a week, he just stopped pooping at night. Mornings, he was quick to poop. I thought he had backstepped.
My habit was to let the dogs out back during the day to hang. And I only go out for the morning and bedtime trips (to ensure his potty time). What I discovered is that he was pooping in the afternoon rather than at bedtime. Now, if he doesn't poop at bedtime, I trust him.